I've been shaving my head off-and-on with the Gillette cartridge 5 blade razor that's a scam to the rest of these safety razor hipsters for going on two decades and have bought maybe two or three costco packs of razors in that time. So about $10/yr. When I'm shaving ~3x/wk I thinkI get a couple months out of a cartridge at least.

Any of the subscription services are scams tho for sure.

I don't shave body hair tho so ymmv.