Objectively...don't do it...unless $70 means nothing to you, which obviously isn't the case.
Buying a snake in bad condition from a pet store will only doom another one to replace it...any pet store with such an animal on display for sale has no heart &/or
no expertise. The snake may be MORE than just not eating, it may be sick. Can you afford expensive vet trips with this snake? Do you actually have enough
experience to rescue it without help? Even if they GIVE you the snake (which they won't), it's likely to cost you more money.
The store should be reported to their upper management (& possibly your local animal control) for neglect & animal abuse, not "rewarded" with your hard-earned
money. Still your call...I understand how you feel...your heart's in the right place, even if you just speak up for him. Report this!