SFU offers OCS conference hosting -- more information can be found at http://software.lib.sfu.ca/support.html
. It may not be as cheap as you are looking for, though.
There are a number of commercial services that are also hosting OJS journals -- you may want to do an internet search for them, and contact them to see if they are also interested in setting up OCS for a fee.
Otherwise, I don't know of any cheap commercial service providers like Dreamhost who do a one-click install type of thing ... but that's not to say you can't install it yourself. I would do a search of this forum on service provider names first, and additionally make sure they meet the minimum requirements needed for installing OCS.