A rock cracked my windshield as I was driving along the 5 freeway. This $11 kit and youtube video patched it nicely!
I did a bunch a looking around and I think this style kit, with its suction/pressure system of injecting the resin into your crack is likely the best. I found this video by Chris Fix super helpful as well. Following his simple directions, I worked on a chip that looked like a 5 point star. I'd say it is now 85% or so invisible and 100% sealed. I am not sure a professional glass repair person could have done much better, but they'd have cost $140 to come out to the house.
Much like the resin I use to repair surfboard dings, if you get this in direct sunlight it cures very, very fast. This kit is easier than making an appointment to have someone else do it.
Permatex 09103 Windshield Repair Kit via Amazon