Below is a comprehensive list of all the items(along with links) used in the Leather Card Wallet Video. I feel this is a solid set of fundamental tools which will be used in practically every leather working project going forward. All of the tools should be able to be purchased for ~$150 or less.
I have also listed all three types of leather I used. I find it most economical to purchase entire sides at a time, although it can be a little intimidating if you are new to the hobby. Sides are typically ~20-24sq ft. which is A TON of leather for small projects like this, and should last you through your entire learning curve. I would imagine you should be able to make at least 50 of these little card wallets from 1 side. If you are not comfortable purchasing a whole side, any 3-4oz leather should work fine, I'd recommend sticking with either vegetable tanned(tooling) leather, or some form of Oil Tanned leather. Also keep your eyes out for sales and remnants.