I don't have the tube in front of me, but I'm thinking it is called Aquamend. The epoxy is green with a white center, exactly like the stuff my LFS carries, but at a fraction of the cost.
It's been a couple years since I bought any so i can't vouch for whether they still carry it or if it's even still called the same.
Aquamend is one brand that Home Depot used to carry but at least around here they no longer do. Word on the internet says it is/was reef safe, but I've never bought any.
Another common one is Oatey Fix-it Stick. I have used that one, but I never will again, nor would I recommend it.
Yesterday I went ahead and picked up several sticks of JB WaterWeld from Lowe's. It wasn't what I'd call "cheap" (if I may use that word) at $5.77 for a 2 oz tube, but it does state
"NSF/ANSI Certified Drinking Water Safe". I don't see that on some other epoxy sticks - such as Oatey Fix-it Stick, or A+B Epoxy Putty (both of which I used in my tank, but perhaps should not have, and never will again).