Appreciation post: My neighbor's yard sale strategy changed my mind about saving for holiday gifts | Budgeting Wins - Freelance Forum - The Community for Independent Professionals
My buddy's kid did something similar, but with video games. He traded in a whole pile of old ones at the store and was so proud he'd paid for his mom's birthday gift himself.
Last August my kids sold their old toys at our sale and matched what I put in the envelope, like @hill.susan said. What hit me later was they learned to see their stuff as potential gift money, not just clutter. Now my son will point to a forgotten game and say "that's like five bucks for Grandma's present." The yard sale strategy taught him to save way more than it taught me to clean.