Look at every critter on the table. If anything looks sick/dying/dead, run away.
If you find a snake you like look carefully at it's body condition. Look for mites. Look for bubbles/mucous around the mouth, listen for congestion/popping/wheezing, and feel for congestion along the snake's neck when you hold it.
Does the vendor have businesss cards on the table or a banner with their business name on it, so you know who you're dealing with?
Ask a lot of questions, like:
- How long have you owned this animal? Some vendors only breed and sell their own, while others will have unboxed the animal from a distributor's shipment a day or so before the show.
- When was the last time it ate?
- Is it eating live or frozen/thaw?
- This animal will be a pet, does it tolerate handling or is it defensive and nippy?
- Probably not an issue with albino ball pythons, but if you branch out into other species you should ask if it captive-bred or wild-caught? If wild-caught, has it been treated for internal parasites?
If you have a smart phone, once you find a critter you like use your phone to do a quick internet search on reviews of the vendor, both here and on the FaunaClassifieds BOI, or even Google.