Given your budget, and it's already been suggested, but here is the break down assuming you are good with cables, stands and mics...
Assuming you are wanting NEW equipment and not used, and assuming you need a pair of mains, and a pair of monitors, the least expensive solution I can come up with. and mind you, this thread was honestly TL

R;
And before I name any gear, we are going to safely assume that not a single component I will mention is going to meet with Modulusman's approval.
Behringer XENYX 1202 (unless I read that wrong, you only need 3 -4 XLR inputs, this will cover that easily). $89.99
Harbinger Vari V2112 600W 12" powered loudspeakers. $129.99 each. ($259.98)
Harbinger Vari V2115 600W 15" powered loudspeakers. $149.99 each ($299.98)
Grand total $649.95
FWIW, spend the extra $10.00 and get the Q1202USB, the USB connectivity will allow you to pipe in / out sound from your laptop. Well worth it for buffer music, backing tracks, effects etc...