It really depends on what you want it for. My view of TLRs would be that they can be superb cameras, fun to use and capable of excellent results. However, they're inherently limited by the fixed lens and lack of interchangeable film backs. The Bronica ETR series are probably the best balance between quality, price, and flexibility - you can find a usable one with standard lens, 120 back, and maybe some other bits for £200 or less here, which brings it down to top end 35mm money.
Whatever you buy, do the research first. I've seen a glut of ETRS which seem to be missing the dark slide and winder crank, while the latter is merely irritating (you can get a speed grip/winder for not a lot of money, weirdly the only person selling the cranks here wants more for them than a winder costs!) the former makes the interchangeable backs useless as you can't remove it from the body unless the dark slide is in place, so you're effectively stuck with the one back. Best advice would be to find which accessories are harder to get hold of separately and then buy one which has them fitted.