Companies that offer a fixed rate recovery of $300 most often are just preforming a software recovery, by running a tool such as Data Rescue. These are recoveries that can normally be preformed by the customer for a significantly cheaper price. When dealing with physically failing drives, the replacement donor drives will normally cost a few hundred dollars, with rare drives costing upwards of $400. Without knowing whether or not donor drives need to be acquired or not will drive the price of the recovery beyond this low fixed rate, and most of these companies will just end up forwarded you to a more qualified recovery center.
When performing a recovery the entire drive must be repaired, there will be no way to determine where the pictures and videos are on your drive without getting the entire drive back into a working state. You want to be skeptical when companies try to return just the videos and pictures as they will have recovered everything already, and not returning all of the data found is just a shady practice.
Most Recovery centers will claim to have facilities all over the US or all over the globe, when in reality all they have is multiple drop off locations where the hard drive will then be shipped to a clean room facility. The cost to build a cleanroom, and then furnish it with all the equipment needed to perform recoveries is too steep for it to be feasible to have multiple cleanroom locations.
The class of a cleanroom is based off of the amount of particles in the air as well as the size of the particles. Cleanrooms can be brought to a class 10 environment, but keeping them there is a costly and time-consuming task. Which is not reasonable with most companies. It is for this reason most recovery facilities will operate at a lower class level such as a class 100, and they will preform a deep clean of their facility if they have a client who is requesting a class 10 cleanroom service.
Many Recovery companies will claim they have the encryption keys to recover from encrypted drives when in reality the companies that creates these encryption algorithms they do not share them with anybody, even after court orders many companies will hold onto their encryption keys. When dealing with encrypted drives, recovery facilities can still repair the drive up to a running state and extract the data but they will have no way to test the integrity of the data without the proper passphrase, which is why you will see many recovery.