I'd be reluctant to consider any used phono cartridge.I agree with Cleeds. A used TT is OK, but do not consider a used cartridge especially it's history is unknown. So here are my comments about the three candidates...
As a Traveler owner, I recommend this TT and try and negotiate a lower price without the cartridge.
The HW-19 is a very nice table but do you know which version it is as its been around since 1984?
Finally, the Rega has a great tonearm but a low cost entry level cartridge with the 2M Red. So don't expect too much off if you go with the Rega and offer a lower price.
Good luck.