I’ve found cheap drysuits for friends on boatertalk.com.
http://boatertalk.com/gear.php
Consider also combing thriftstores for a waterskiing drysuit – these are cheaper and heavier, but still effective drysuits. I’ve found a couple in my casual browsing.
How much webbing is canyon dependendent, too. Funny, though, how when we were beginners we carried lots of webbing (100′) just to be sure (more than we needed). As intermediates we carried the bare minimum ( “hey we’ll just cut rope and use that”). Now we carry lots again. Not a bad cycle to be in. I was glad in the beginning to carry too much than too little, than slowly whittle away at the kit as experience grew. I like having 2-3 precut/tied shoulder length slings as well, dozens of uses.
Sticky shoes are Really Nice but understandable that you want to avoid buying. The tennis shoes will get you through a couple of canyons just fine. A couple of cheap ideas for sticky shoes we’ve used: 1) Zion Adventure Company http://www.zionadventures.com/ will frequently sell there old rentals at the end of the year. The shoe will usually be in decent shape but have only a trip or two’s worth of tread left. These can also be resoled – check out http://www.climbingresoles.com/ Who will resole approach shoes for $30 with 5.10 sticky rubber.
2) You could also try this with your old tennies or light hikers if you really like the fit and think this will be more economical than buying new shoes.
3) Finally I’m reminded of Tim Schiller in Fresno’s “Homemade canyoneeros” that he and his friends made in the 80s using old skateboard shoes and converse. Tim bought a BIG sheet (they still have some left after dozens of resoles) of sticky rubber from 5.10 and simply made there own approach shoes.
Good luck! Steve