Parents with car seats their kids have outgrown, listen up: Walmart is offering a sweet deal — that also helps the environment.   Beginning Monday and running through Sept. 30, the retail giant is running a program where shoppers can bring their old car seats to a store’s Customer Service department in exchange for a $30 gift card that can be used online or in-store, Walmart shares in a release.   The company’s inaugural Car Seat Recycling Event, in honor of National Baby Safety Month, is being held in conjunction with TerraCycle, “and each component will be diverted from the landfill,” the release states.   Vice President of Walmart Baby, Melody Richards, says in the release that car-seat safety “is a top priority for Walmart's Baby department, so we wanted to use our size and scale to create an event that offered unprecedented access to trade in an outgrown car seat for a gift card — perfect for using on your baby’s next car seat.”