I'm by no means an expert, I think one solid option would be to jump into whatever Rega you can afford new or find used. With the Rega/limited budget, you can take comfort in the fact that there is a ridiculous number of incremental upgrades to be had for [relatively] cheap whenever you can afford it down the road. There is certainly an element of fun in the upgrade projects, although I'd try to enter the Rega line above the RP1 - go used if you have to. Consensus seems to be that while you can upgrade the RP1, the better units will benefit more from the upgrades.
There is a robust and fairly active community of owners in the Rega sub-forum of Vinyl Engine, and should you decide to move in that direction, they will be able to help.
Their is no shortage of affordable cartridge endorsements to be had there, but folks seem to love their Nagaokas on the Regas.
Good luck!