[dubya]

My area has something called POP club (power of produce?) at the farmers markets. Kids try some sort of produce, decide if they like it or not, and then get $5 of fake money to spend on produce or seedlings. It's really been interesting watching how my kids decide what to get, and how much, and negotiate the transactions. In the spring we often get starter plants for the garden. Even if you don't have such a club you might consider a "produce allowance" when you go to the market.

Not much to do with STEM, so I'll add that my youngest really likes changing the batteries in his toys, especially if a screwdriver is required.