Cheapest I saw was $96ish each shipped, couldn't find a set in stock to see if they were cheaper.
I think there are way better options than the Magpul Pros, I haven't seen a set of Troy's or DD I could fondle first hand.
I want a set of the Troy Tritium Battle sites strictly for going to the chicken coop at night, that or a 1 or 2x night vision optic, preferably thermal.
Get a Modlite and don't worry about the Tritium.