I disagree Get a Sharpstone but make sure its legit, and not a knockoff Half baked goods and I think Vape World sells Sharpstones $20-25 is the cheapest you'll get fora grinder that will last you 5 years without any metal shavings in there
IDK, I got a 2.5" ebay grinder and it seems to be decent quality. Haven't seen any metal shavings, the screen is nice, and it was only $10
I bought a cheap aluminum grinder off ebay for $8, might review it when it comes. Im hearing aluminum might flake, but not sure