I made these last year:
I bought a Speedy Stitcher for $15 and read the instructions that came with it. I had never done leather work of any kind before. Sewing leather is pretty simple. I buy scrap leather online from belt factories. I spent about $50 for the fork bag and the tank bags. If you look at the G/S thread in my sig and skip to about page 50 you'll see a write-up about it.
I had a great time making the bags. I keep leather tools on the bike and I'm always sewing something when I'm sitting next to a campfire on road trips. It's a lot of fun and you can get cool stuff from doing it. Tandy Leather makes all the tools and nothing is very expensive. You need a ruler, a razor knife and the speedy stitcher. If you want to get fancy Tandy sells rivets that come with a simple punch for a few dollars.
I used lexan from Home Depot for the map case. A piece twice that size cost $4. If the bags sit empty they tend to fold in so I backed the leather with lexan on the top case.