I live in a small town in Bavaria, no chance I could get any of the equipment locally.
I always have to order things online so.
If I want to get a good deals on things like tools, I even have to order abroad.
I have a Leatherman Surge and a Charge TTI and a Micra for the Mrs coming from the US, also some Nike running shoes and Maxpedition pouches.
Just figure: I paid $50 for a pair of shoes that retails 120 Euros over here. (I got three pairs 
)
Shipping inside of Germany takes a maximum of 2 days. I bought some LiPos from the Hobby King warehouse in Hamburg. Took 3 days, which was odd. So, there's no way around it
If I buy for more than 40 Euros online, I can return any item for free within 2 weeks. I don't even have to pay the return shipping.
On the subject:
I'll have to see how much more expensive the Mega is. I'll probably be wanting one anyways.
Is Saintsmart the company that makes them or are there other options?
It's kinda hard searching on ebay because I get a ton of results for Aruino Uno or Mega, which are shields and other accessories.
So, I can't really figure out, how much they should be.
What do we do displaywise? Do we directly try for a readout on the android phone? Or should I buy a display? If I buy a display, it would be nice to make it one that is large, flat and rugged enough so I could use it on the bike's handlebar for readouts to see what's happening.
I would also like to have some sort of a keypad to be able to have some user input. Can you recommend anything there?
Sensors shouldn't be too expensive. I'll have to get some thing wire to hook them up though (smallest I have here is 2.5mm²)
Are there a so many options for hal and temperature sensors?
This is one of the stores, we have here:
I don't particularly like it because it is too expensive, but the things they have, I can find cheaper elswhere.
Actually, reichelt.com is nicer. You can even save your shopping cart there and share it with other people and they're overall cheaper. I'm going to order some banana sockets from them anyways.
So, what else should I get to start out?
@ Henry. Besides a multimeter, how can I see, if it worked? I see the point of the appeal to be able to use the keypad and output a signal with that. I think both can be pursued at the same time. Right now, the most important thing is to get the basic hardware together so I actually have a chance at success. Without bricks and mortar you can't build a house.
These are two arduino display options I found.
http://www.ebay.de/itm/1-8-128X160-SPI-TFT-LCD-Modul-Display-PCB-Adapter-SD-Card-Socket-fur-Arduino-/170923463903?pt=Bauteile&hash=item27cbd514df