I have been doing leather craft for about ten years now and you can get alot of money tied up but you don't have to. I started with a kit from Tandy I think it was the middle kit it's on the web sight. I think it was a hundred bucks. It has all your basic tools you'll need for belts and wallets ect. I would also recommend Al Stohlman's book on hand stitching it's a good resource and has plans for a stitching pony. I built one and I think it cost me 7 dollars for materials. If you are planning on doing some stamping of tooling you will need a good flat and hard surface to work. They sell some 12 x 12 (I think there marble) slabs at Tandy. When I got mine I went to a monument place(build headstones) to see if they had any scrap they would sell me. The guy ended up giving me a headstone that was missprinted. It's a great work surface. If you sign up for Tandy's wholesale club you get a pretty good discount and a free patern and stamp every month. I think it's 25 bucks it will pay for itself one your first order with the discount usually.
Good luck TJ