GTX 970's go on sale all the time from anywhere from $320-370ish, depending on what one you choose, which is a good price for that card if you're willing to pay it as it has great overclockability, decent power consumption, great avg. frames in almost all games on the highest settings in 1080p, access to shadow play, 4gb of v ram, and has plenty of power to stream. It's just the best price per performance gpu out there imo. But if you want other options I'll list others I believe are the best in their price range.
~$170 Radeon R9 270
~$200 Radeon R9 280
~$250 Radeon R9 280x
~$280 Radeon R9 290
~$330-350 GTX 970
I've seen some GTX 760's on sale for like $170 on amazon a few weeks ago, but atm I wouldn't take it over a r9 280 at $200
The r9 290 beats the 770 at the ~$300 price range as it offers more memory, higher memory bandwith, higher pixel rates, less idle power consumption, though the 770 boasts a higher clockspeed and effective memory clock speed. But part of this is off set by the r9 280's ability to overclock. Plus the 770 is overpriced imo sitting at like 320ish.
The sweet spot for me as I said above is the 970 if you can find one on sale for ~$350 but then again you're in a completely different financial situation than me, hence why I posted the other options. If you want to talk more in depth about it we can always talk in ts.
Hope I helped homie