Well, at $4 / album it’ll take a while to amortize the $6,500 for the cleaner.
I think it is a great idea to try their cleaning. Some albums are “cleanable”… as in it makes a huge difference… some not. With experience you can learn to tell by looking at them (well, most of the time).
One of the major variables involved in what used vinyl sounds like is your turntable / cartridge. There is an huge drop in noise with an audiophile table. Part from the table and part from the cartridge… the stylist most older records were played on old record players with big stylists… so a high end cartridge drops down into the groves further and they can sound much better as long as they are clean(ed).
What is your system? There is a place under your ID to put photos. Very helpful for us to understand your system and where you are coming from.