I am have a LITTLE experience with building.
You have more hardware than I've ever had at one time. So if you gave me that $100, and I had a LITTLE experience building, I'd get wire and tools. Obviously you might have some of this stuff already, or might not want to go this route. Again, just me...
1. Fully agree with EJ... batteries. Samsung 25r's at Liionwarehouse. 5 bucks each.
2. Ohm meter. USA Ohm Meters are good, but too expensive for your current budget. You can find a throw-away (cheaper) one that a few people suggest, then test the accuracy with a regulated mod, other people's ohm meters and/or Steam-Engine.org (put your coil in and see what it says the ohm reading should be).
3. Wire. I use 26 gauge the most for singles and 28 gauge for double twisted. 32 comes in handy. (I confirmed these sizes with a few of the really good builders here, when I said I wanted to drop down to three sizes only.)
4. Flush cutters. Amazon has a pair for $5 that is very popular. CHP-170.
5. Ceramic tweezers. I like the curved ones better for tweaking coils, versus the sharp tips.
6. Cheap needle nose tweezers. You can probably dig one out of a finger/toenail kit for free.
7. Scissors. Really good pair. I have a Fiskars Soft Touch Micro-Tip Pruning Snip that is one of my favorite vape tools. For cotton cutting. But quite honestly, any old pair will do.
8. Needle nose pliers. You can get a cheap one.
9. I like having my Coil Master jig, but I use it to wrap by hand. And I only make 3mm for all four of our setups. So I probably could have found a 3mm nail.
10. There has to be an even number right? Um. A dollar-store ruler with inches and cm/mm on it. Can't believe how often I use that thing.