Two questions I would ask before buying.
1) Is the seller trustworthy? Essentially, until you redeem the coin, you don't know if there really is any bit coin associated with it.
2) What the heck do you want physical bitcoin for? If it is part of your "prepper" kit, gold or silver will be more widely accepted. If it is just so you can put it in a safe deposit box at the bank / coffee can in the backyard, an engraving tool and a piece of PVC pipe will meet the need.
Anyway, good luck.