Grow Lights vs Heat Lamps: I'm a Dork

I was looking for some type of light for the top of our corn snake's cage to keep him warmer this winter. I want to keep the heat down a little to save money (via propane savings) but don't want Willy to get too cold. I wasn't sure what I was looking for and found grow lights first. I'm such a dork! He needs a heat lamp, not a grow light. Does it look like he needs to grow anymore? I think not! He's not oregano to stick under a horticulture light!

As you can tell, I know next to nothing about snakes. Willy is the pet of my ten-year-old son (and dad helps him care for him and feeds him). The feeding thing? Yeah, that's kind of gross.