I have a Big Agnes Sand Mountain Insulated Air Core. R value 4 and 2 1/2 in thick for comfort. I bought it on sale on RREI Outlet for $35. Not there anymore, so BA Insulated air core would be a more expensive alternative. Get an air mat rather than self inflator, but make sure it contains insulation. Lots of people swear by Eped down mats, but they are heavy and expensive.