back in the 90s there were companies that would repair those kind of chips for 50 bucks. when I had Allstate for insurance, they would even waive my deductible if I had the window repaired instead of replaced, so they would pay the 60 bucks, and the company that did the work came out to where my car was. (work, home, school, behind your basement whatever) I would assume they exist today as well, and even if the cost is now 80 bucks, it is still cheaper than a replacement...
you could usually only see a slight imperfection where the rock chip was when it was done. and as long as the chip could be covered in its entirety with a quarter, they could repair it.
State Farm insurance did not have the waive the deductible clause and I had a nice star shaped rock chip in my Intrepid one summer and did not have the extra 50 bucks to pay, so I waited until the weather got cold and turned on the defrost which was right under the chip, and just like that, I saw the cracks run the entire lenght of the windshield and State Farm ended up replacing a 350 dollar windshield the next spring.
AJ