Cheap tanks in the W. Cola!
I just went by St Paws Thrift Store on 12th st in West Columbia and picked up 2 20 longs and a 10g for $10 total. They still have a 10g and I think either 2 or 3 more 20L. I think the individual prices were $3 for the 10 and $5 for the 20L. The tanks were donated from Carolina Wildlife and the lady that runs the store said they were planning on donating more too.
If you need some cheap used tanks might be something to check out!! If you go, ask about them as they're all out back.