Hi Ephraim,
I fully understand you budget requirements. Years ago I built an entire rifle with the tools shown below because it was all I had.
The gouges, both #7 sweeps, were used to remove the bulk from barrel channels, lock/trigger mortice etc...
The curved flat chisel was used to “stake” the vertical sides of locks, bbls etc... and then clean it up to make it ready for the inlet black.
Like Okieboy said, scrapers are easy and fun to make. I just finished a final lock fit with the two scrapers made from old lathe tool bits. The bigger brown one I made almost 40 years ago for round barrels. It was made from a pc of O1. Old files and chisels work well. The flea market chisel on the right is now ground to a 20-something degree chisel point, but years ago I ground it to 6 or 7 degrees point and used it as a scraper to clean up the bottom of octagon barrel and trigger plate channels.
Bob D.