>> I presume you'll use Code 39. However, which code you use depends on how much you want to store in the code. 39 is common, I believe, for inventory management in the U.S. <<

Correct. The Universal Product Code (UPC) bar codes you see on grocery items are code 39. It isn't truly universal -- the UK has its own standard for grocery products, as do other countries -- but in the U.S. it is pretty darn close to universal. Most if not all of the big grocery chains stopping carrying items without UPC codes 20 years ago.

Mike