Welcome to Leatherworker.net!!
I hate to be the first to say this, and possibly discourage your interest in leather work, but $100 is not going to get you much in the way of tools and leather. I suggest spending what you need to for the leather, and use whatever tools you have instead of buying a bunch. There are many, many, many people who have turned out fantastic pieces of leather work that didn't have "leather" tools. I'll dig around in a bit to see if I can find it, but we had a member from somewhere over in Scandanavia 'show off' an absolutely beautiful artistic piece that she made with ....a manicure set. The only tool I can think of that you'd need that is commonly only found in leather work (besides stamps) is a diamond awl. That refers to the blade shape, not any particular material. One of our members reports making diamond awls out of bicycle spokes, so if you're handy with tools, you can make a lot of your own. I have made several stamps from SS bolts.
So....local sources you can find things-
Hobby Lobby- they have several items you can use, including stamp sets, needles, thread (I use the waxed linen sold as "On A String" brand)
Hardware store, grocery store, and wallyworld- Mop-n-glo is a reasonable substitute for Resolene. Dap Weldwood is an excellent leather adhesive, Olive Oil can be used to condition leather, Deft lacquer makes a nice finish, bolts make nice stamps after a little work...so do nails. Forget the 'leather sewing needle' with the large eye because it breaks easily. Just get a pack of needles from wally world's craft dept., I think it's a little under $2 for 8 needles in different sizes. You need an overstitch wheel? No, you don't. Use a fork to lay out your stitches, and start saddle stitching (two needles)- it'll pull down nice and tight to the leather. Edger- use sand paper to shape the edges.
A good knife- you can use pretty much any knife to cut leather. It needs to be scary sharp and you need to be careful, even if it means more than one pass to cut the leather. You can also use scissors.
Need a tool to make a line a consistent distance from the edge? Get a $2 compass from the school supply section. If you absolutely HAVE to get a stitch groover, get the free hand one and put it in the compass, replacing the little pencil. Now you can make lines a LONG way from the edge, or right next to it as you want......and a freehand groover in a compass will do circles.
Swivel knife? If you have to make do, use the square 'chisel' blade in an exacto knife. Heck, Al Stohlman (IIRC) started out with a sharpened screwdriver.
In short, the tools we use in leather working were developed to make jobs a little easier, but are in no way the only tools you can -or should- use. Need little bitty circles as part of a background? Take the ink ball out of pen, and start tooling. Need an interesting background for foliage (trees and bushes)- put a torx bit on a handle and start stamping. Get creative! ......and hey, if you start using some of your wife's make up accessories for working on leather, I bet you she'll find a way to get you some leather tools.