Just remember not all good deals are such good deals if you are taking on someone else's problem and you don't have enough experience to deal with it.

Look first at the snake's enclosure, that will tell you a whole lot about the snake inside. Is the enclosure clean. Has the snake been kept on proper substrate, offered hides, a clean water dish, a controlled heat source - that sort of thing. Look at the snake next. Does it have retained shed. Does it have an appropriate girth to length look about it. Does it have clear eyes, a clean vent, undamaged scales, no mites, etc. When handled does it feel muscular and in good healthy shape (watch how the owner handles her snake, let her remove it from the enclosure and observe their interactions - that'll tell you more things about how that snake was really cared for). When you handle the snake listen carefully for clear breath sounds - no clicking, wheezing, popping - no fluids or mucus in or leaking from the mouth - no crustiness around the mouth or nostrils indicating dried secretions.

Get as much information on this snake as you can as far as where she got it, when she got it, if it's ever been housed with other snakes, if it's been properly sexed at any point, if it's ever been ill, etc.

If you own any other reptiles make sure you fully quarantine this snake for a good 90 days or so. I wouldn't switch food types right up front. You need to let this snake settle in properly, take a few feeds from you first before you start messing with what this snake knows as being food. It's enough stress on a snake to change owners - I wouldn't add in the stress of an unknown food source right away, just my opinion.

Be ready for vet bills. You may not have any but if you take on other people's snakes, you take on whatever good or bad husbandry they gave that snake.