Reply to Speakers vs Monitors?

I am just getting into the DJ scene as a sophomore at San Francisco State University. I went with the Numark mixtrack as my controller with the Numark Dj Io souncard. The only item I need now is a set of speakers. However I am not sure if I should go with something like a sony hi-fi speaker system, or some cool monitors like the krk rockits. I need something that will be loud enough for me to use at parties with a usual occupancy of 20-50 people since most SF/ Daly city homes are small but also something compact for my home usage. Another issue is that being a college student makes my budget vert tight to around $200. Ive been told that 1 rockit is able to fill up a small living room. But I am leaning towards getting two incase I end up being in a garage with more space. Any advice or comments would be highly appreciated. Also if I do end up getting two krk rockits is it necessary to buy an extra subwoofer?