Let alone if its a bacterial infection, all the snakes this person has could be infected.
Walk away, find a different supplier.
If money is an issue, look up the local Herp society in your area, they might have rescues that you could adopt, as well as local help and guidance.

When I purchased my pastel the breeder asked if I was in a Herp society or club, and that the best thing I could do for my snakes was to join one. She was right.