Personally I use Excel to keep track of my ever growing electronic component stock.
There are a number of commercial applications in the market that offer upto complete ERP solution! Some offer a free limited version which is sometimes quite difficult to setup.
Anyone found a good open source app for home use?
I don't know but scripts/macros/VBA with Excel might be enough.
Or you can also do a lot with an SQL database. Customizing/automating a database for home or a small operation probably isn't any more difficult than configuring an ERP system.
Or, maybe just use index cards. 
A long time ago I needed to organize some information and scheduling for equipment calibration. I told my boss that would write a computer program (it would have been in regular-old BASIC). He was a wise boss and he said, "Organize first, before you try to computerize your mess." I actually ended-up using index cards and I never needed a computer application!
One of my pet peeves is people using spread sheets when they really need a data base. When people were complaining that Excel could only support 32K lines I remember thinking "they are already 2 orders of magnitude down the wrong path". Full blown databases like MySQL or PostgreSQL can be very intimidating, but they are overkill for a home user.
I would recommend looking at SQLite which is simpler but still powerful.
https://www.sqlite.org/index.html
For a user interface consider DB Browser for SQLite.
https://sqlitebrowser.org/
This is the combination I use for personal data bases.
You can save spreadsheet data as a .csv file and import it into SQLite.
Disclaimer: I worked the the database area for decades and am biased.
(I do use the LibreOffice spreadsheet where a spreadsheet makes sense - not everything needs a database 
.)
I mentioned LibreOffice as a suite... it also has a dB manager...
I have looked at LibreOffice Base a couple of times. From the description...
Base is a full-featured desktop database front end, designed to meet the needs of a broad array of users. Base caters to power users and enterprise requirements, providing native-support drivers for some of the most widely employed multi-user database engines: MySQL/MariaDB, Adabas D, MS Access and PostgreSQL. In addition, the built-in support for JDBC- and ODBC-standard drivers allows you to connect to virtually any other existing database engine as well.
I found this to be more trouble than it is worth. You have the complexity of a major database and then you have the client-server connection interface. Obviously I could do this, as I did it as a job for years, but for personal use it is way to much work. The home hobbyist in unlikely to be a "power user" or need "enterprise requirements".
I used dBase (original through dBIV) then OpenOffice (LibreOffice), but only local and never was a power user... I like "free".
I use my brain and labels on my boxes / drawers.
Sometime when digging I find stuff I had forgotten I had, feels like a new toy to play with 
I just use EXCEL.
For storage, I use to use Add-A-Drawer but have graduated now.
I now have multiple large plastic boxes, numbered 1, 2, 3 etc.
I use large Ziploc bags for storage and label them A, B, C etc., these go in the boxes.
Smaller Ziploc bags go in the larger Ziploc bags, I label these 1, 2, 3 etc.
A part in EXCEL has a number like 3-F-4 for say a capacitor 100nF,
Located in box #3, large Ziploc bag F, small Ziploc bag #4.
In EXCE, each part has a line, includes: Part Description, Box Location #, Part Type, Quantity on hand, Price per unit, Seller name.
100nF Box #3 in the furnace room, Ziploc bag F, component Ziploc bag #4 . . .
Customising / automating a database is not really my weekend option for fun. I was looking for a ready made solution . Something like binner. If only there was a similar open source version...
Pencil and paper ?
'Apps' or databases that record 'stock' are only of value if the initial quantity of stock is correct and that every time you use a component you adjust the stock.
My 'stock levels', for home use, are completely visual, if I am building something and when I for example need to use a 10K resistor, and there are not many left, I order more.
Having to enter into a database or spreadsheet to update 'stock' every time one of my DIY projects requires a component sounds completely daft or obsessive.
Meh. You need a database when your data gets very large, very distributed, or has complex access mechanisms/requirements.
That's "hardly ever" for the average hobbyist (or even small-business) inventory.
Agree. My first engineering job was with a very small (< 10 employees) company. Our "inventory control" was when the shipping clerk was told to make up a kit for e.g., 100 units of a product and she discovered that one of the bill of materials items had dropped below its reorder level.
Once a quarter, she did a complete, manual inventory tally and that was mostly for tax purposes.
Technically correct. However, virtually everybody understands a spreadsheet, while the vast majority of people get lost in the basics of a relational database.
Ideally, people would use a database for this kind of thing. Then again, ideally, we would know our parts inventory by heart. Truth is, in life we stumble from one compromise to another. The ones who are trying to get it 100% right every time are generally stuck at square 1 for eternity.
I know about database basics (well, probably more than that; I'm fairly well-versed in SQL) and yet, I use Excel for most of the applications I "should" be using a database for. It's just quicker to set up, quicker to do mass permutations, more intuitive, etc. Overall, the "wrong" way is simply better from a practical viewpoint much of the time.
Yeah, I'm not a fan of Base. Like much in the OpenSource domain, it's "technically a good solution" and therefore practically of limited use.
How about Excel without any VBA or bells & whistles. You know, so that it always works, and keeps doing that into the future as well.
KISS, people.
A database has advantages when you want to do searching, sorting, grouping and other operations it is designed for. You can do some of this with spreadsheets but it is awkward and may take multiple steps. Fit the tool to the job.
No need to update stock every time you get a resistor! I just use the BOM list after all components are soldered... Some apps even let you upload BOMs from eg KiCad.
Sure, although the things you mention specifically work very well in a spreadsheet too. A proper database generally has less redundancy (if properly designed) and of course can more elegantly handle relationships between entities. However, that still doesn't mean that most users can actually benefit from these advantages as they require insight into how databases and DBMS's work. The vast majority of people don't have (or really need) this knowledge.
The proper tool for digging a trench may be an excavator, but if you don't know how to use one, a spade does fairly well especially for a modest trench.
If these components come in strips, I'd leave them in strips:
I simply use the standard Windows Notepad application (one file) to maintain a summary of each order I make and some tags to help searching (say NMOS) or the label on SMD components etc. I use the same file for items which are waiting to be ordered.
I have several large boxes, one for each of (1) Hardware (that is prototype boards, wire, fasteners etc etc), (2) Passive Components, (3) Semiconductors, (4) (yet) Unsorted Components, (5) Modules, (6) abandoned/re-engineered projects. So I know where to find the stuff.
I usually buy component sets (as in the above picture) and can put multiple strips or ammo packs in bags and, if a particular value is getting low, I mark the bag for a reorder.
I have no intention of maintaining a full stock control system. The stuff is generally so cheap that a large safety buffer of parts can be held (space allowing).
The disadvantage of this approach is that when I do have to purchase a special part from Mouser, Digikey etc., then I have some difficulty bulking the order out to meet the minimum requirements for free postage and may end up adding a board or something I'll never get around to using. The alternative approach is, of course, not to hold any stock at all and to buy only exactly what is required for a specific project but this also has disadvantages.
This is what I've settled on for the last few years. Otherwise I found myself buying things that sat around until they were obsolete because I didn't have time to look at them. I have lots of jellybean components but I limit the amount of "specialty items" that I keep on hand.
