well, ive found that the best cheap monitors ive seen are the Yorkville ysmip's active moniters. I suposed the passive version would be much cheaper. Personally i wouldn't go any cheaper, and i can't really afford to pay double for the Event 20/20's.
Try to find some Yorkville YSM1 series monitors. I have a pair of YSM1i monitors that I got for $200 new off ebay. Course, then you need something to power them, so you may want to search for active monitors (YSM1p). Some people here have the M-Audio Studiophile monitors and like them - do a search of this bbs and I'm sure you'll find something.