there's a woman in our community who makes floggers out of bathmats -- the clear plasticy kind. she calls them squiddies or cephalopods, and they have a heck of a bite.
another friend made a fantastic fucking machine out of a kitchenaide mixer. ^_^ it's the coolest thing. he got a double sided dildo, cut it in half, and added bolt attachements. the thing has 10 speeds, but i can only take it up to 4. hahaha
it's awesome. kitchenaides turn up in thrift stores every now and again.
someone else in the community made an AWESOME vacuum bed out of PVC pipe and and shower curtains. it works gloriously and turned me into a fan.
www.sub-shop.com has a lot of really good sales, too. i got a ballgag from them for $3. and of course you can make a cheap one yourself with a practice golf ball (they're like tiny wiffle balls) and a shoestring.
i made a bit-style gag from a purse handle. haha -- it actually works really well. i like it.
snake bite kits only cost about $4 from walmart in the camping supplies section, instead of $20 that's charged for them on kink/toy sites. walmart also sells $1 bandanas you can use as blind folds. i also got a great flat hairbrush to use as a paddle from dollar tree. =p haha $1!
as others have said, clothes pins, riding crops from TACK STORES, the varieties of chain and rope available at hardware stores ... you can come up with all sorts of things for fairly cheap. =) the first set of restraints i had were made for me by my late M, out of recycled belts.
scope out the well-known sites around the holidays when they have sales. i got a wartenburg pinwheel and a vibrating egg from JTStockroom once for about $10. =p