Yeah this is my only issue with refurb electronics. Imo they are often a fantastic option because people are too scared to purchase something used. BUT the biggest problem is battery degradation. For that reason, I would actually avoid most refurbished phones, laptops, and tablets. That is…unless they are either relatively new release models (within about a year) or if the seller states the battery has been replaced.

Laptop batteries seem to vary wildly in price depending on the model. Some can be very cheap as the people responding to you say, but still others are very expensive like you say. Also, when most people sell a particular battery for $100, if you happen to find a seller from China that sells the same specced battery for only $20, the quality becomes a bit suspect. Battery safety is not something I’d really want to play with too much.