The travel window is tight for this price, but there are slightly higher fares for travel in earlier months. For the $466 price point, travel is available from May 5 through May 21. Travel to Europe Sundays through Wednesdays, and return from Europe Mondays through Fridays. A 7-night minimum stay is required.
This sale is unadvertised and prices may jump at any time.
We're also seeing some other cities with roundtrip fares to Prague (PRG) in the $500s for winter and/or spring travel.
These are Basic Economy fares, which only include carry-on baggage and do not include advanced seat selection. A checked bag costs $60 each way. If you need to check a bag, you'll be better off purchasing a Main Cabin Economy fare for $55 more each way, which includes one free checked bag, standard seat selection, and is eligible for ticket changes/upgrades.