I started casting with 2 cavity Saeco & RCBS molds but a few years ago I could find the model of molds I was interested in used but well taken care of for 50 bucks so I figured the first thousand boolits covered the mold .
I later after getting a little experience with harder metal molds acquired a few aluminum and brass molds that cast just fine , but need to be handled with care .
I'm seeing used aluminum molds for sale with the top of the blocks just gouged out horribly , properly using lube and temperature stops the damage - but to a new caster by the time it's figured out the damage is already done .