There's a few places, try Total Truck....there located off the Seward Highway, just before you get to the Fire Station/Go Kart Track/ Diamond Blvd Exit.
You can also try the palce up in Mt. View....real close to the McDonalds...quickest way to it would be off the Glenn @ the Airport Heights/dodge dealer... You might also try the store there at 36th and Seward highway and another one is on the Old Seward like your heading to Diamond Blvd. I can't remember the name of the place but I think it's just before 76th on your left...last I remember there's a RV dealer on the hill across the road from it.
Then if you feel like driving out to the Valley go to Wasilla....take the trunk road exit then take the frontage road....you'll pass gator glass, Builders bargins then there's the truck store (next to the carpet store)
Hope this helps.....