Grow bags are the cheapest.

personally....I got 18 5 gallon buckets at home depot for like $1 each and then drilled holes in the bottom. works great.

but you need smaller pots. The hardware stores dont really have good prices on their pots. but you could ask a nursery or garden store if they have left over pots. like the square ones that plans sometimes come in. I see lots of places getting rid of extras. They wouldn't be durable for tons of grows, but they'd last you a few and then you can replace the ones that crap out.

Ive used grow bags and they work just fine.

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