IF YOU SENT THE SAME REEL OF FILM TO DIFFERENT FILM TRANSFER LABS, YOU WOULD SEE A GREAT DIFFERENCE IN QUALITY.
There is no standard, no regulation, no watchdog agency that insures the quality of movie transfers and be assured, quality varies greatly, regardless of price. There are places doing telecine transfers, which involve a film projector projecting an image onto a surface or in some cases directly into a lens, and a video camera recording that image. This is how it was done years ago when home movies were archived to VHS tape and many places still do it this way, with quite a variance in quality. A film scanner that takes a picture of each frame of film is far superior to the older method. Even with the best scanner, the skill of the operator and the attention given to the scan determine how good the quality will be. Unlike a projector and some scanners, nothing touches the film except gentle film edge guides: no projector claw is needed, no chance of damaging film sprocket holes or burning film frames. Film is transferred in HD quality and made into a DVD, Blu-ray or video files.
The cost depends on the amount of film you have and whether it is silent; magnetic sound; or optical sound. Be careful if you think you may have sound movie film: many online services will charge you for a film transfer, but your sound movies will be silent.