How about make your own, go find some silicone molding compound. You can get it online or local if you look around.
If you get the stuff, it is easy to use and make a pattern. You could even fill the cracks if they are deep enough with wax, then make the mold, which will even fit the edge of the pattern.
You could even if your really cheap, just wax the heck out of the area and use normal caulk. you would only get one use out of it, but for four bucks what do you want.
Alumilite - Products - Silicone Rubber