inventorofthefuture:
I will need it within a week of parts arriving. It shouldnt take more than an hour to build for someone who knows what there doing.
Plus the time for sourcing and ordering parts, figuring out the exact footprint of all parts for PCB (perfboard) layout, and testing after it's build (do you have any code already?), and understanding the circuit itself (easily an hour study - the part numbers in the image of the instructable are all but unreadable so have to be cross referenced to the text, and it being an instructable must be carefully checked for errors).
By the way, those 4-digit LED displays are also available with driver IC on board. Makes like a LOT easier when it comes to programming them, and for keeping the LED display off the board, just a few wires connecting it. Saves significant build time, too. That way I may be able to do it in an hour, but I like to end up with a neat looking board and that takes time, too.
It can all be done quite quickly (a few days for the parts to arrive; a day or two for assembly & basic testing; shipping from my place to where-ever in the world you are usually 1-30 days), but for a single unit it's of course not a USD 50 (I assume that's the flavour of $ you mean) job.