XB: Sticky Add To Cart Button

After our long-time sticky ATC app informed us they were discontinuing, we needed another. There's quite a few out there - even in the free tier - and we tried many, but XB was able to do what we wanted best out of the many we tried. Their support team is very helpful - and it's nice that they are in my time zone! And I like that they have a suite of other useful apps (also, some free) which should mean they play nice together.