One of the things that I love most about hemp jewelry is the fact that you can do it on all sorts of surfaces. At one point I think I was using my big toe for one piece, a purse for another, and a lava lamp covered in tape throughout my early hemp career.
If you're looking for ideas of what type of surface you can use to make your hemp jewelry on, here's a few that seem to work out the best. Right now I'm using a speciality made hemp board by Catz In the House that has all sorts of nifty pegs, a strip of cork down the middle for easy pinning, and a big metal o ring for mounting. I also have a big, thick sheet of foam board for when I need to work on macrame that benefits from having a zillion pins stabbing through it. The macrame board was like $30 so it's certainly on the pricey side compared to the foam board, which was probably a dollar at most at any craft store.
Another popular option, and a great solution if you'd like to be portable with your hemp creating, is the clipboard. The clip holds the top of your piece perfectly, and it also tends to be the perfect size if you're looking to make some bracelets. Clipboards are a great low cost option as well. You can also just work with a soft wood board – just make sure that you have the ability to push a tpin right through and you should be great with just that.