what can I really do with it?
Well, that depends:
What band is it? These are single band radios. You cannot change what band it is on.
What features does it have? It'll have analog, but it might have P25 digital. Might have trunking. Might have some other cool features. Or, it might not.
So, here's what you can do with that:
If it's a band that you can use.
If you have Astro25 Portable programming software
If you have a programming cable
-or-
You have someone who can program it for you,
You can set it up to listen.
Good for conventional systems.
Using it to monitor trunking is a whole huge ball o'wax that comes with a bunch of challenges. Don't expect to use this to monitor a trunked system. If it has the right features, you can make it do it, but there's a lot of risks. Get a scanner. Get a scanner. Get a scanner.
If you have a valid FCC license:
And you have a radio that will work on the band/service you are licensed for
You can program it to transmit.
If it's VHF, you can use it on the 2 meter amateur radio band.
If it's UHF, and it's the correct band split, you can use it on the 70cm band.
If it's a 700/800MHz model, there is no where you can legally transmit with it, and no, you as an individual cannot get a license on 700 or 800MHz, there are no itinerant channels, no ham channels, no "free/don't need a license" channels, no matter what anyone tells you.
If it is UHF, it is NOT legal for GMRS, but some may ignore that and use it anyway.
If it is UHF, It is NOT legal for FRS in any way, shape or form, but some may ignore that and use it anyway.
If it is VHF, It is NOT legal for MURS in any way shape for form, but….
What it is:
Probably a 20+ year old radio that would be in need of alignment.
Probably in need of a new battery.
Probably in need of a new antenna.
If it was used by EMS, probably in need of sterilization.
Or, use it as a handy door stop.