We sell with the RXA-30 antenna. It's for WAAS & works much better than the patch. Kind of like Raven's Helix vs. a patch. That RX510 you priced is full list + it looks like, unless that included subscription. Contact info is in my profile if you want to discuss pricing.
What is your application for it? If not planting, you should be good with the better WAAS antenna, but if planting, you might want to consider that 510 for OMNI or GLONASS. They also have a RX410 for OMNI of beacon, doesn't have GLONASS.