I've been needing to get some saddles for my BC Rich Mockingbird filed down just a bit, but I don't quite have the experience or tools to do it myself, anyone have any idea for an average of how much that would cost? Was asking a guy a guitar center, but he wasn't the tech and was suggesting it would cost more than their set-ups...which seems bullshit.
Because they need to be filed down? The way they're designed is just not very good, saddles completely lowered, neck is set-up perfectly but the action is still too high.
Put the file down and step away from the bass. Unless you have an early Badass Bass bridge then you never need to file down the saddles.

What you need is a shim. This is essentially a small piece of card or veneer that you put in the neck pocket to increase the angle of the neck, giving you more room to play with the saddle height. It's a very easy and reversible mod, I've done it on three of my guitars.

I just had a quick look online to find a decent guide for you but I can't find one so watch this space.
Looks just like the one on my Spector, based on the Hipshot A-Style. Unsurprisingly that piece of shit needed a shim too.

My recommendation would to be to get a small metal file and shave a few mm of the bottom of each saddle then. Others online have suggest using nut files to increase the groove depth but that's most likely going to play hell with the vibration of the string and any rough edges will destroy your strings.

Good luck and get a bolt on next time.
More or less what I wanted to do, but at the same time, the grooves are slightly worn, so they need a slight bit of filing, too, but I don't have the tools to do it myself.
That bridge appears to have adjustable saddles, so can't you just adjust the screws and lower the saddles?

Now; if you are saying that the saddle notches are too narrow for your bass strings, then that is another matter. But even then, those saddles are not the solid metal blocks like those on a Badass II bridge, so filing them with a "V"-shaped Mill Bastard File is probably not an option. You might even have to have a very good craftsman do it, and that would not be cheap. But check it out at a shop with a good repair tech.
"Maybe this world is another planet's hell?" - Aldous Huxley
It's already completely lowered as low as it will go, the bottoms either need trimmed or the slow the string sets in needs filed down. It shouldn't need too much.