This sucks!

Just complaining that yesterday I accidentally left my insulin (Lantus and Humalog- both brand new) in my car for an hour. It was hot out, so I was concerned but I figured I'd try the Lantus one more time to make sure it was ruined and of course it WAS. (my blood sugar spiked like crazy for no reason) So two (EXPENSIVE) vials of insulin completely ruined because of my stupid forgetfulness! I know I've read it on here before, but what do you guys use to keep insulin cool in the summer. I usually just carry it in my purse, but now I'm thinking I need something better. I don't want to ruin any more!