6950 is not really that much better than a 560ti in a bunch of games and depending on your locality, may be more expensive. Not to mention it is older tech than the current 7000 series so power consumption at idle is higher etc. At least get a 6970 if you want a bit more future proofing. If you could still unlock the 6950s that would be great but unfortunately not anymore. Have to plan in terms of future use especially for gpus.
I can understand price limitations but there is no point going for sub par and having to upgrade every few years.