Green Cooler
From Super-wiki
The green cooler has become a recognisable part of Sam and Dean's personal belongs. It is a vintage Coleman cooler. It appears in 6 (or 8) episodes (see note).
Note: A similar cooler is seen is season 8, but they are slightly different models. It's hard to know if it's a deliberate change or the original cooler is missing and they replaced it with a similar one.
Also, Benny's cooler from 8.09 is the same style as seen in The Benders (1.15).