There are a number of websites with plans/ideas for home-made bondage devices.
Ropes, chains, screw-eyes, padlocks (or snap-rings for the cautious), etc. are readily available from your hardware store.
Most thrift shops can supply a selection of leather belts that can be cut down for cuffs, collars, or whatever.
Pet stores can be a source of attractive devices as well, some of the more elaborate collars can be quite attractive.
Use your imagination!
I am a big believer in making as much of your own gear as possible. Not only is it (much) cheaper, it also personalizes the item, which for Me and subbie is a really big deal.
It's also smart from a quality control standpoint. No more nasty surprises when you finally get that 200 dollar flogger in the mail... and its made from cheap leather somewhere in southeast asia.
I think most of us have been there.
Sartan's working with leather is a good starter site. If you have a good, lifestyle-friendly leather supply nearby, that's the best of all possible worlds. Just ask for help in the technicals.
As for "found" bondage gear in stores, I would start with the pet shops. Not only are the leashes, collars etc. of pretty high quality, they are cheap and readily available.
After spending considerable time and effort building wrist/ankle/thigh/waist restraints out of very good leather, subbie admitted she liked the feel and efficiency of our twenty dollar investment in black nylon webbing restraints from the pet store.
If that interests you, I would say buy the widest, thickest, and softest nylon collars possible. And don't worry about size... I was initially, but apparently there are some pretty big doggies out there...
Any more specific questions/comments are hugely solicited.