Someone else on here posted about a good result with going to Best Buy, which I did, too. They sold the InvisibleShield for about $20 and installed for around $8. Lifetime guarantee. Lady was doing several in a row. You cannot tell anything is on there. Worth the cost to have it done right, for me. I would not try to do window tinting, either. When that goes wrong, everyone knows it .
Good luck on whatever choice you make.