With all the expenses of the Eurotop tour I wanted to save money and I went really low. I have a reservation at Econo Lodge Inn on International Drive, a few blocks from the Rosen, for $32 plus tax the night, or $144 for 4 nights including the 12.5% tax. Of course, considering Orlando weather, those few blocks could be under torrential rain (not uncommon) or searing heat (very likely).
I just checked the Rosen and they are asking $155 a night standard rate (without the meeting special) but they still have rooms available all those days. Last year they had a last minute special to fill the rooms, lower than the yo-yo special and with breakfast included. So you may want to keep an eye for that. With the economy hurting, Orlando is hurting even more, so there are great discounts available (and low airfares).
I hope you find a roommate, it is a great way of saving money.