-Prices valid while supplies last or until 11:59pm PST tonight. -Amazon Baby items have free returns available for 90 days from date of receipt. Britax Pioneer G1.1 Harness-2-Booster Car Seat, was $198.03 yesterday, now $135.69, a record low price from Amazon. Britax Marathon G4.1 Convertible Car Seat Jet Set, was $232 yesterday, now $173.99, a Want to continue reading this post? Click here!