You can use just about anything - old wooden planks, pallets, old doors, iron or plastic sheeting... The important things are to make sure you're not introducing dangerous or poisonous chemicals - so treated materials can be a problem.
You also want to make sure liquid can drain away out the bottom - if it can't you can end up with a really unpleasant gloop in there that can sour your compost.
I have a compost bin made of old fence panels that's about five years old and almost fallen to pieces - that's bound to happen because, after all, it's full of rotting vegetable matter! It's still done a pretty good job thus far - and it cost me nothing.
You can wire it together, nail it together, string it together... whatever works. Tucked away in the back of the yard it doesn't have to be a thing of beauty, it just has to do a job! Be creative - what's the worst thing that can happen? If you leave a pile of old vegetables on their own they'll turn into compost eventually - a bin just speeds up the process.
If you're interested in worm composting, there's a video on my hub about vermiculture here: