Music costs - DJ, band-HELP!

Can anyone help me with some guidelines on the cost of a DJ or a band? I know a band is generally more expensive and goes by the amount to members etc. But what is the general price range? I dont even know where to start with this. Any suggestions are greatly appreciated

There are several hotels in the area on Jericho Turnpike- There is a Marriott in Syossett, the Best Western, there is also the Huntington Hilton on Rt 110.

My DJ is $750 for four hours (five hour reception minus one hour for cocktail hour where he will not be playing music)...includes a FEW party favors for guests (maraccas, glow necklaces, YMCA kit, etc.). And, I'd hope to give him up to a $100 tip if applicable.