/diy/ - Do It Yourself

Put two of these in the non-movable part of the lid, maybe 2 inches in from the hinge, with the hook on the inside of the can.

When you wrap your garbage bag, pull the bag to the hooks and punch a hole in the bag to slip over the hooks. When trash goes in it'll pull the bag down against the hook and it should stay put. If it doesn't, bend the hooks in such a way that the bag stays on. Think IV bag hanging.

When you punch the hole, make sure you still roll the edge of the bag a little and put the hole below the roll. That effectively makes the rim/roll of the bag into a thicker, stronger place for the hook to hold and it won't rip the bag open.

Benefits: simple, probably a $2/can fix. Simple to detach the bag. Only modifications are small holes in the lid and a tiny bit of thread/bolt sticking up. Use acorn nuts if you want a smooth, safe top. Should work.

Cons: anybody can steal the hooks. Maybe you can find some sort of rivet solution using the same premise of an internal hook under the fixed part of the lid though, pic related is just the first hook I thought of.
Might also pose an issue if the trash is above the lid, as you'll have to dig under the lid to undo the bag depending on how hooked it is. You might be able to find a happy middle ground of hook bend that still allows you to pull it off at the right angle without falling off.