I am looking for hand tools for my woodworking hobby. I need a wooden mallet, cooper's adze and whatever I can find. Where can I find these used and usable, not for show or collecting? New ones are so expensive.

Try garage sales or estate auctions. We live in rural Indiana, and you can find anything under the sun for not very much money at an estate auction. My dad even got a huge roll top desk for $500.00 once.

Good quality old ones are even more expensive and if not, the hard edge bonded to the softer strong metal may have been sharpened away.
In any case, go to big flea markets that have people with that kind of stuff - Canton Texas First Saturday Sale for example (not one where used video games are a feature) and be prepared for a lot of walking. If you see someone with old tools, tell them you are looking for basic woodworking tools in usable condition and they don't need handles. They may pull stuff out or direct you to another vendor that has some. I got a couple of good cold chisels for free one time.

There are lot of ways to ones problems and you can solve them easily one you have better suggestions ….like the ones above…keep going mate ;-)