What's the best way to get cheap housing for a group of 5? Book ahead? Get one room?

We're traveling as a group and paying individually for rooms seems ridiculous. Is it possible to rent a room and just pay a flat rate instead of per person? We're looking for the most reasonable rates, esp. at hostels. Any ideas? We've heard conflicting information regarding whether you should book ahead or just go and look for housing when you arrive. Thoughts? Your help is VERY much appreciated.

I'm especially interested in getting housing around Shannon/Limerick, Ireland. But we'll also be in Paris, Vienna, and maybe Dublin and London.

Try searching the area you are going to for hostels. They are cheaper to use. This is what a lot of people do when traveling thru Europe. I also know there is one in Monterey CA so I'm sure other cities have them.

http://www.hostelworld.com/countries/usa...
http://www.hostelbookers.com/
http://www.hostelhandbook.com/

always call ahead most motel/hotel rooms with 2 beds will only allow 4 people in ROOM without getting a roll-away
or getting 2 rooms the ideal is to find a motel with a room that has 3 beds ...still may have to pay extra for anyone over 3 in room . anything over 2 pay extra person in a 2 bed and anyone over 3 adults in a 3 bed will pay extra.
but as a motel manager we have to ask how many people even if u booked it on line or over the phone.
it is Florida statue that manger has to know how many in the motel if a fire Marshal comes