One sheet of plywood, a lid that stays up on its own, and a floor you can see again.
This fits in a car
About 80 lb of materials. Comfortably inside what a car carries (200 lb), so any shopper can take it. ⚠️ 3 items on the list have no weight on file, so the real load is a little heavier than this.
Before you start
Sand every edge and corner round. Plywood only, never pressure-treated wood, on anything kids handle. The lid supports are the important part: a lid that slams can trap fingers or a head, so no latch, and keep the hand-hold slots open for air. Put heavy toys low so it cannot tip.
It lands in the shopping form, where you can edit anything and say what you think each thing costs. Nothing is ordered until you send it.
How it goes · about a weekend · some experience
Cut a hand-hold slot near the top of each end panel with the jigsaw. It doubles as an air gap.
Glue and screw the front, back and ends around the bottom panel, clamping as you go and checking it is square.
Iron the edge banding onto the raw plywood edges, fill the screw holes, and round over every corner with the sander.
Prime and paint the box and lid, and let it dry for a full day before it gets used.
Fit the lid with the piano hinge, then fit the two lid supports and check the lid stays open wherever you let go of it.