No one has responded directly to the questions in the last 2 sentences of your post, so I'll go out on a limb: I think you would have to spend at least $300-400 to find a better used moving coil cartridge, and you'd give up some the important performance qualities of the Shure.
For reasons I've never understood, the audiophile community has a strange reluctance to give the Shure V15V the respect it deserves (although TAS magazine now rates it as "Best Buy" in their "Recommended Components" list). When used with a good medium-mass tonearm, mounted to a good turntable, the Shure V15V (particularly the latest incarnation, the V15VxMR) is an outstanding value in phono cartridges. It offers very flat frequency response, superb tracking (arguably one of the best tracking cartrides made at ANY price), warm musicality, very low noise, user-replaceable styli, etc., etc. It's moderate output (3.0 mV, as I recall) is best suited to a phono preamp of medium gain (about 40 db), and it needs to be terminated with a 47k Ohm impedance, but other than those two points, it's quite "un-fussy".
So, in short, unless you plan to spend quite a bit more money, I think you're well advised to stick with the "Shure thing".