If the seller is willing to dump in a few gallons of bleach, and slosh it around, why not?

However, I'd guess the seller isn't nearly as motivated to get the pool really clean as you are. I imagine you'll have to do some more cleaning and drying yourself (either at the pool's present location, or after you get the pieces home).

Our only pool experience so far is with a 1000 gallon donut pool (similar to the one you currently have set up, I think), and I'm always impressed with how long it takes to thoroughly clean and dry the thing before packing it away for the winter. I don't think a seller, who wants to get rid of the pool, and isn't charging much for it, will do that kind of work for you.

Of course, maybe it's OK to pack a liner up wet and dirty, and plan on doing more cleaning next season when it's set up again... I'm not optimistic, but haven't actually tried the experiment.