My suggestion is talk to your neighbors about it and find out when is an ok time for you to play them louder. And then when watching movies, listening to music, or playing games at other times when they want it quiet you will just have to turn your subs down.
But the problem is you said your budget is $300. You won't find a pair of worthy subs for $300. I'm honestly thinking you should be looking in the $500 to $700 class for each sub. You could always start with 1 sub and then add another identical sub down the road as money permits.