Just print it, take it to the supermarket stick it in the trolley, shop, return the trolley and take it with you. It is also a nice way to do a bit of... publicity/promotion for yourself. Do some shopping, leave the chip in the trolley with your message for the next customer to pick it up!
1 Euro shopping trolley chip. Simply, print it, put it in your key ring and away you go, ready for shopping.
If you print one for you comprehensive partner he/she will also understand the usefulness of your 3D printer!
If you find it useful and you wish to customize it, let me know and I will upload the scad files.