A cheap power head and heater can probably be found locally for under $20 each. Cheaper on the internet.
A rubbermade container , ~30 gal., will cost about $8-$10
A thorough cure will last 3-4 weeks. Check water parameters, once ammonia and nitrites are gone, then the rock is "cured"
You can also get rid of unwanted hitchhikers by keeping the salinity low. However, you may get rid of "wanted" beneficial hitchhikers too. Your call.
MCF