I noticed when I took Tucker out to play yesterday he started shivering after 4 or 5 minutes, whereas he's normally running all over the place, chasing the air

.
He's very shy so I first thought he was scared by something, but I'm afraid he may actually be getting cold as the temperature has dropped quite a bit in the last few days (from 70's to low 50's).
I'm just curious as to what types of coats you guys use and where you got them. I'd also be interested in buying a used one if anyone has one their baby has outgrown. I live in such a small town that only has a Wal-Mart and they hardly ever carry anything cute, so everything I get Tucker has to be bought online.
Thanks!