Barnacle,
Here's my thoughts. Take a calculator, figure out what you can afford to spend on store-bought bullets every year or month or whatever.
Buy a Lee aluminum mold, or better yet, two of the same bullet (cast faster that way).
Stash the extra money it would have cost to get an iron mold in a coffee can. Then stash all the money you would be spending on store-bought bullets in the can.
Buy the time your cheapo, Lee Mold wears out go back to all the coffee cans you've now filled with cash.
Now decide whether you want to buy a iron mold, or just replace the Lee mold, and use the rest of the money for a new gun!
You COULD do that. But if you're like me (and the rest of us) you'll sack the coffee cans much sooner and use the money to buy primers and powder and just shoot more.