I know being cheap is the key to success but if you plan to use any catalyst(dryer) or silica, this tank is the worst. If you don't constantly turn and agitate the entire contents you'll get dry sealer in the corners etc.
PS. polyethalene(plastic) is not suitable for open road use. These tanks are used in vans. The walls are sometimes not thick enough and CAN? break, distort etc.
This apparatus is not suitable for sealcoating. Most of the THEIF-TIME gypsies use these tanks becuase they cost about $40 at the right store.
Save your money and buy a a real steel tank.
As far as the pump go on ebay. It's called a Diaphram pump and takes a compressor and about 6 HP engine.