How to prevent my iPhone screen from cracking more? Anyone ever replaced a screen themselves?

Last night I was sitting on my floor, with my computer on my lap and my cell next to me. I reached to get something and my lap slid and hit my phone. Of course, because I have the worst luck this year and this is the third or fourth time, it cracked.
The crack is pretty small and start near the home button and goes up a bit.
I can't feel the crack so I'm assuming it's either really minor or or inside the phone somewhere?

Is there anything I can do from preventing the crack to spread or getting worse in anyway?

I've already fixed it two other times ($125 each) and I really can't do it again at that price.

Or, has anyone ever bought one of those fix it yourself kits on amazon or anything. They range from like $30-$60 which would be more doable. Was it easy, did you like it?

There are countless videos of screen replacements.

All it takes is a $12 screen kit (includes new screen and tools) and a hair dryer.

Don't let yourself be scammed by the stores.

Also, try taking better care. 3 times means you're the problem.

Get a rubber otterbox case that the iphone fits in.