So I'm spinning at my first gig in 3 weeks at a University party. There are some speakers set up where I will be spinning but apparently we're renting more speakers as well. Our budget is somewhere in the area of 400 dollars Canadian (approximately 270 dollars american). My question is what are the best speakers to get to rent with this budget? Also what amp should we rent to power these speakers? The room has a capacity of about 300 people, and I know nothing about speakers or amps so help a dj-in-training out

You can't really answer this question without knowing what will be provided for you already.

For example: if you aren't getting any subs, hire some cross-overs and subs