For me personally, liner installation fee, although expensive is money well spent. Watching the installers, its a lot of work and there are a number of little details that came up that I didn't even consider before they started. For example, they ended up replacing the jets (eyeballs), jet, skimmer and main drain covers. In addition to that, there was some minor repairs made to the floor. You'll need to ask whats include in the price.
I was planning on linking a video, but there are lots of them posted on youtube. If anyone know of a video that is really good, hopefully they'll post a link, but nearly any of the ones I glanced at will give you an idea of the kinds of things involved.