To get started Po-Boy style you'll need:
Leather - you HAVE to use veg tanned leather. Chrome tanned leather is NOT toolable, and will rust your knife. I use shoulder leather. I get my leather from Siegel of CA. Their prices are MUCH better than Tandy, but their service is not as good. You'll have to call and give friendly reminders. But the price is REAL good, and orders of 75 bucks or more get free shipping.
Tools - Po boy style.
-A kitchen fork for spacing stitches. (Save your ten bucks from the overstitch wheel.)
-An ajustable groover to inlay your stitches. This keeps them from fraying to nothing.
-Needles. DO NOT BUY YOUR NEEDLES FROM A LEATHER HOUSE. Their needles tend to snap, and it becomes a PITA. Get them from a sewing store, or Walmart. Get ones with a big eye to thread your waxed thread.
-Waxed thread. I use nylon because Mike Tea told me to.
-Contact cement from Home Depot. Don't waste your money getting that stuff from leather houses either.
Thats good enough for a start! Get'r done. I mod a leatherworking forum, and there is one at KF too. If you'd like the address, pm me.