Depending on your insurance, glass is covered differently.
My mom paid for her rear window because she thought that the deductible applied, etc (like everyone above). But the next time I was present and told her just call the insurance – auto glass is covered without the deductible. All she had to do was call and they sent a person right out to fix it. You can get the dings in your windshield fixed by the insurance with no deductible too (they'd rather fix the dings than pay for a whole windshield).
We have USAA and comprehensive covered it, I think.
Anyway, you might want to poke around your insurance before giving in and buying a new window out of pocket.