Now while I could immediately start up with the whole… fill your room past capacity and split the cost part, we’re not going to do that. ; P
Conventions usually have a list of hotels working with them that have a select block specifically set aside for the con. However, remember that pricing you find on the convention’s site and check around on the hotel’s specific site. You’d be surprised when you check for deals, especially if you’re a rewards member with said hotel. From there, I suggest checking booking sites, such as Expedia and Kayak… You’d be quite surprised at the deals you can find on there, and might even be able to get a bonus thing added to your room! 😀 Compare all the rates and get the better deal!
Now yes, sharing the room at con is a good idea because you can split the cost between your roommates. However, part of enjoying a convention is getting sleep so you’re not a cranky panda wandering about like a zombie. At most, I suggest ever having to the room is five people. You can comfortably get a roll-in bed or air mattress even with two beds fitting 4 people there, usually, cause there are hotels where that can be argued. As cosplayers, we take up a lot of space, and you want to have your room be a comfortable sanctuary when the con takes its toll. So, don’t get carried away with the room sharing!