I definitely wouldn't call this project cheap. All in all I spent about $100 on the tubing and specialty tape from identi-tape.com

I bought my tubing and connectors from mcmaster.com

Product #5372K525 & #50375K574

The PSI on this tubing was 195, while the recommended PSI is 100-160. I don't notice much of a difference, the hoop is just a tad harder and heavier. I ordered 25 ft. of tubing which was enough to make one regular size hoop and one giant tandem hoop.

Next time I think I'm going to try some 1" diameter tubing, perhaps from USPlastics.

The really tricky part is the taping and I had really hard time with that, especially the gaffer tape. I highly recommend that if you want to use vinyl tape you go for the quality stuff from a specialty tape store, because I used regular electrical tape from Lowe's on my rainbow hoop and it's already peeling off. I've only used it once, inside the house.

And the 600 calories an hour thing is a bit of a stretch...