Welcome to the forum, from SW Missouri....you have definitely put some thought into this. My suggestion would be buy the tools you need to do the job at hand. If strap goods, then maybe get a strap cutter. When you decide to get into stitching, get some chisels. I started out the same way you did. As I made products for family, friends, and neighbors, I charged according to my skill level. Both parties were happy, and I had money to go buy more supplies. As my skill increased, I charged a little more and was able to buy more tools, stuff to enhance my hobby. There are many ways to go about it. Look for inexpensive items as well. Get you a granite slab for next to nothing from a counter top company nearby (a sink cutout). Ask your friends if they have a cutting mat they're not using.
But when you buy tools, don't go cheap. Find decent quality tools at reasonable (hard to do these days) prices. Tandy would be the bottom for me. Don't buy the cheap stuff from overseas on Amazon. The quality is just not always there. It's a crap shoot. Weaver, Springfield Leather, and others have good tools. You will pay a little more for them, but you won't be disappointed.
Also, don't buy a tool for something you can do without, until you can afford to get it to save you some time. An example is a corner punch. You can get a nice corner punch for several dollars, but at the same time, you can trace around a round object then cut with an utility knife, then sand smooth.
I am sure there will be much more info coming your way, but you may also want to search through the forum. This question gets asked from time to time.