For an over the counter product, I would go with 3M Performance Finish. For online ordering I would go with Four Star Ultimate Paint Protection or an apply-and-walkaway kind like Optimum Optiseal or Ultima Paint Guard Plus.
I don't have Optiseal, but I have a small 4 oz bottle of Ultima and used it 20+ times and still have half a bottle. It's really easy to use and it holds up well after a few layers. You pretty much just wipe it on and leave it. No need to wipe off. It's easy enough that I use it after every wash which is about every 1-2 months for me. It looks especially nice on lighter colors (i.e. silver, white, gray).
I use Four Star strictly for looks since it doesn't last for more than a few months.
I don't have Optiseal, but I have a small 4 oz bottle of Ultima and used it 20+ times and still have half a bottle. It's really easy to use and it holds up well after a few layers. You pretty much just wipe it on and leave it. No need to wipe off. It's easy enough that I use it after every wash which is about every 1-2 months for me. It looks especially nice on lighter colors (i.e. silver, white, gray).
I use Four Star strictly for looks since it doesn't last for more than a few months.