Go to your local library and look for whatever "leather working for beginners" book they have and read it. Then go to the local craft store and buy a scrap of leather, and some thread. You can also youtube for how to make a wallet videos. You don't need many fancy tools use, a fork to mark where the evenly spaced holes should be, then a nail/hammer to punch the holes, and needle will work for sewing (though I'm told a real leather needle is much better and cheap if you buy any tools).

Note that your book will show you lots of fancy patterns you can put on the wallet with expensive tools. It is up to you if that is worth it.