Need to clean out your garage and get a little extra spending money? Walmart is hosting a child car seat recycling event this week that will pay $30 for seats your child has outgrown.   Nearly 4,000 Walmart locations are taking park in the event, which runs through Sept. 30. Customers can take their used car seats to the service desk and receive a $30 Walmart gift card that can be used to buy items for their child.   Parents can swap up to two seats per household and booster seats are not eligible for trade-in.   The event is being done as part of the company's observation of National Baby Safety Month. Walmart is working with TerraCycle to recycle the car seats and keep them out of landfills.   “Through the Walmart Car Seat Recycling Program, traditionally non-recyclable car seats are now nationally recyclable,” said Tom Szaky, CEO and founder of TerraCycle in a statement. “Through this event, we expect to divert the plastic equivalent of approximately 35 million water bottles from landfills.”   Competitor Target recently completed a car seat trade in event. Life to date, that retailer says it has recycled 11.9 million pounds of old car seats.   The program comes as Walmart looks for ways to keep its competitive edge against Amazon and other large retailers. The company is also more susceptible to the China tariffs than some other retailers, because so many of its products are made in that country.