Tesco are doing a version of the Thermarest right now. Can't remember how much, but they were a lot less expensive.
Eric
size and weight is an issue. I'm not going trekking with it but if its heavy then walking around with all the kit on my back won't be fun!
The Airic is at the top of the list at the moment. Anyone have any feedback on the cheaper ones?
An alternative might be a backpacking airbed. I bought one for £10 a few months ago after my Nomad SIM sprung a leak. Its a 6 reed job which is lightweight, folds up small, is very stable and comfortable and if you want to improve insulation you can take a piece of foam mat to put on top.