My perspective is a little different that the others. I believe that a sturdy bench is an absolute necessity having tried it on all sorts of jury rigged benches. I build benches out of 2x4s and 3/4" plywood using two ladder frames, one for the top and one for a shelf with 2 2x4s screwed together for each of two legs at the front. The back of the top and shelf are screwed into studs in the wall with 4" lag screws. You can made do with a 6' bench, but an 8' bench uses an entire sheet of plywood. You assemble it all with drywall screws and 1/4" carriage bolts.
As for tools, you can get away will just hand tools if you do it Mark Silvers way, and you can buy a lot of good quality antique tools on ebay relatively cheap. All of the best builders I know use a relatively small set of tools for most of their work. Many of the tools they made themselves. You do need to be able to make your own tools to be a top notch gunsmith. You just can't buy everything. Mostly, you are going to need to make planes, scrapers, a scratch stock, and special chisels. You will also need various forms and mandrels. I actually have a list of all the tools I have on my various benches when I am building a rifle. I intend to put it on the blog on my web site (
www.markelliottva.com) but just haven't gotten around to it yet. I will endeavor to do it soon.