My very thoughts, but used sometimes is just as good as new. I would worry about transportation rather than cost first. Getting out of the basement is going to cost a pretty penny so add it to the cost of the tank...
Pianos are touchy though, the front facing two legs are meant to hold weight and not have weight shifted on them so they usually break when moving. Movers know this and charge more as pianos are expensive.. But a tank that size is going to be expensive.
