Over the past two months I have given my spare tube away to six different guys standing on the side of the road cursing their spare tube that wouldn't hold air. Did they have a $5 tube? Don't know but they were all miles from home wondering what they were going to do. In all cases my Conti race 700 tube got them back on the road. For me, I'm going to spend whatever it takes for a tube that works when I need it.
Reggie's, the local Trek dealer, sells them for I think it's $4.65, so that with tax it works out to exactly $5.00. So they do still exist. (If you want the long presta valve it's $6.00)
I've seen plenty of tubes that have different boxes and brands only to find the same tube inside - all the same markings, manufacture name, etc. Multiple LBS here in Indy sell tubes right around $5.
I had to go look and see what I had in the garage. 3 tubes on the shelf. 1 Bontrager standard (2 standard if you count the one in my saddle bag) and 2 Bontrager Race X Lite. Standard had a price tag of $6.99 and the Race X Lite's are $9.99. I thought that was reasonable compared to say latex
