Comment by RodgerTheGreat

I'm extremely biased in recommending it, but Lil is semantically very similar to Q, entirely free, and intended to be beginner-friendly: https://beyondloom.com/tools/trylil.html

It's not as powerful or concise as K, but it gives you some of the flavor of an array language tucked inside what resembles an ordinary imperative/functional scripting language.