Hi,
A note of caution.
That does indeed look like a spider.
But before you bring it home have a good quarantine area set up, read up on the spider wobble so you don't freak out, and ask yourself, and them, why they are selling it.
Inspect it carefully to see if you will need to treat for mites or anything.
People who don't look gift horses in the teeth tend to end up with lame horses with bad teeth.
Also double check the sex if you can.
dr del