I would suggest to save up as much as you can for this initial speaker investment.
I was lucky and bought my yamaha hs8's on sale. They were comparable to the krk price point, but at an extremely better quality than the krk's.
If you want to get down to the nitty gritty of your mixing to a point where, something will continue to annoy you until you fix it in the mix, then i suggest yamaha hs8's (8's because of the bass replication. In so that you don't have to buy a sub).
other wise i wouldn't know what to tell you.
My friend bought some presonus 8 inch not long ago and he likes them.
You should save up around 1000$usd (not sure what country you're from) and go see see the different speakers available at local shops/guitar centers/sam ash.
I also say 1000$usd, because you'll have to buy wires and stands. Stands are optional, but if you have the space to place them, lordy it's nice.