What to buy for best wifi router range?

I was looking at the Asus RT-AC5300, but $300 for a router....that seems crazy high priced. I'll never use half the stuff in it...just need something that can handle the distance and has good/stable software (even better if I can throw custom firmware on it and jack up the range if needed). 

*Can anyone recommend a router that should be able to handle that distance and still deliver good performance?