Now I called Cruiser Customizing (in the original post) and brought to their attention the difference in price and told him I could get both sets for $70 and if I add some windshield cleaner from the Innovex site I qualify for free shipping. He said he'd price match the caps since I was ordering two sets and give me free shipping to go with it. So I didn't have to order anything additional.I asked if he'd give the same deal to anyone else if I posted here and he said only if they buy enough to exceed the $75. Not sure why I got the special deal, but you may be able to argue it and get them to give it to you anyway.
I've had the TireGard version of this for several years and it sure makes keeping an eye on tire-pressure easier (especially with bags in the way of getting at the rear tire.) These look like a great less-expensive option. Please follow-up with how you like them, once you've installed them and used them a while.