I tried the cheap tubes recently. Junk. Had one or two blow-outs a week. Bought some good quality Continentals and have not had any blow-outs or flats since.

Even in the short-term, you don't save any money buying cheap tubes.

Here's my math:
Cheap tube period...
two tubes per week for three weeks at $6 per tube = $36

After I bought two "expensive" tubes for $10 per tube = $20

I have been running on the $20 dollars worth of tubes for 8 weeks now without incident.

The cheap tubes blew out and were not repairable.

I will not be buying cheap tubes ever again. I learned my lesson.