One of the eye-opening things you quickly learn as a parent is how expensive child car seats are.   Spoiler alert for the childless: Car seats are super-expensive. Also, your growing child will cycle through various car seat stages. Take it from me, a father of two.   These days, the average convertible car seat price is roughly $175 — although it ranges from $75 to $400 or more, depending on your needs, taste and budget.   One way to save money here is to take advantage of car seat trade-ins. Babies R Us, Toys R Us and Target have these in-store events every once in a while.   Right now, it’s Target’s turn. Target is holding a nationwide car seat trade-in event April 17-30.   It’s basically a two-week window to bring in your old car seat and get a coupon for 20% off a new one, good through May 31.   Once or twice a year, Toys R Us and Babies R Us do the same thing, usually offering a 25% discount. This usually happens near the beginning of the year.   The Car Seat Cycle of Life   These car seat trade-ins are especially useful because at some point, your child will outgrow their current car seat, or it’ll expire.   The federal government offers car seat guidelines based on your child’s age and weight. Here are some useful guidelines:   Infant seats: Newborn to 2 years, or 30-plus pounds. All-in-one seats: Newborn to 12 years, or 120 pounds. Convertible seats: Newborn to 6 years, or 65 pounds. Booster seats: 6-12 years or 120 pounds. What happens to the car seats that Target collects? It’s teaming up with recycling company TerraCycle to have them recycled into new products. They expect to keep 700,000 pounds of car seat materials out of landfills.   Consumer Reports has good tips on when to trade in your car seat:   When your baby is a year old. When your baby gets too big for their infant seat. It’s simply time for the next step. When your car seat expires. Yes, car seats have expiration dates. Check your car seat’s manufacturing label. They’re typically good for six years. After that, you can’t resell them on Craigslist or at a consignment store. Your Turn: Have you ever traded in a car seat?