That’s a cool idea! I’d like to see some.
I have a few small ones if you have 6 months to a year or more to save. I use savings and cash back apps, as well as take surveys for a little bit of money. Sure 50 cents to a $1 for a survey isn’t much, but after a while year it adds up. And 1-10% back does too. Another way is to save change. Literally change, put in a container you cannot easily get back in to. Then after a year take the change to one of those machines in grocery stores or to your bank. The machine counts it and you get your cash in bills. My brother did this and saved a whopping $580 in change, half of it looked like pennies too.