TejanoTrackie 

The problem I have with buying tubes from the various lbs in my area is not so much the cost as the selection. They often don't carry either the brands that I want or the sizes or valve lengths and have no interest in stocking them. For example, one lbs carries only one valve length in presta, 60mm, so that it will fit all rim depths. Thing is, many of my clincher wheels have shallow box rims that don't need anything more than a 36mm valve stem and look positively goofy with a 60mm valve sticking out, which also tends to rattle. When I made a bulk purchase, not only did I get a much better price, but also a mixed selection of 36mm and 48mm valve stem lengths, which worked out perfectly for my various wheels and rims.