I've found that all inexpensive tubes are not the same. Some tubes tend to have crappy presta valves, where the valve leaks, or the valve separates from the tube. On some tubes the valve doesn't mate to your pump head just right.

I used mostly Nashbar-branded tubes for years. They were heavy for the size tube I used. I assumed they would be more puncture-resistant with all the heavy rubber. I never had any real problems with them.

A couple years ago I ordered several "Q-Tubes" - a new generic QBP brand, priced as low as Nashbar's tubes or better. I bought regular and lightweight version Presta Q-tubes in the sizes I needed. The regular Q-tubes weighed less than Nashbars at the same size, plus they were much less porous - even the lightweight tubes were less porous than the Nashbars.

With the Nashbars, I'd lose 10-15psi in a tire inflated to 80psi overnight, and with the Q-tubes I'd lose less about 5psi. I rarely flat so I can't say one is better than the other in this respect.

All the Q-tubes I've bought were made by Kenda (printed on tube). This QBP brand is offered in more sizes than the Kenda-branded tubes also sold by QBP, and at lower price. One thing I liked about Q-tubes is they came with regular length valves. Ten years ago I used to buy Performance Lunar-lights, which was a tough lightweight tube, and at some point Performance stocked these only with aero-rim length 60mm valves, which defeated the purpose of a lightweight tube to some extent.

If you're looking for a decent, inexpensive tube, try Q-tubes:

http://aebike.com/model-list/q-tubes...-t554-qc30.htm