Although there are in Thingiverse (and in another places in the internet) already many shopping cart coins, removable or not, here is another one.
I combined two size coins in one gadget.
It has been designed, and tested only, for the Swiss 1 and 2 Franc coins, and for the shops in the area where I live.
Update: I have updated the design. Now you can put it on your keychain and still use both sides. I also added the version for 1 and 2 Euro coins
I added the Fusion 360 file. You can adapt it for your coins by changing the radii of the coins and the thickness of the coins. Select a thickness between the thickness of both coins.
For instructions see the two screenshots
To use it: Insert the right diameter size in the slot of the shopping cart, unchain the cart, rotate the gadget to the left or right and take it out.
I designed this for my convenience. Use it responsibly. Not to "steal" carts, or to leave carts in the parking area uncontrolled.
Best Value ABS
Very simple to print. Should work with other resolutions as well.