It depends. What do you have now? You could certainly buy a gpu for 250, but we need to know if it will fit in your system and if your power supply is up to the task. Give us some specs on your PC.
This build is even cheaper, at $560 and this is pretty much the cheapest build you can get if you want to play new-ish games at decent fps and 1080p, although the CPU in this build will bottleneck slightly, unlike the first build: