Best router for 1800 sqft home

1800 sqft all on one level is a challenge. 

you can probably get 1 router to cover it but you'll probably have dead spots or slow spots on the peripheral. 

And the 100-150 is a bit of a challenge because router prices have increased lately. for instance, the R7800 would usually sit around $170 over the last year but has been pretty high lately. 

In terms of 1 router solutions, I'd probably recommend the R7800 if it drops in price.

If it was me, I'd be watching for a triband mesh system so you can have better coverage. Again,1800sqft is a large area to cover