You don't need a compression sack for a thermarest. open the valve, fold it in half twice and sit on it, when it stops hissing, close the valve, unfold and start rolling towards the valve. When it gets tight, open the valve again and keep rolling. close when done. Once you've got the air out that way, there isn't much more to compress, but it will stay that size pretty well. The self inflatables don't come with patch kits, but a mcnett seam-grip kit with the tenacious tape works well, and is all you need.
Inch and a half is pretty thick, that will be a comfy one. I have the old trail, and its pretty thin. Good for a skinny lightweight like me though.