A very small amount of real money gets you enough coins to basically open all the boxes.
You earn coins by hitting the goals, or you can purchase coins for real money. You get one “box” of scenarios for free, subsequent boxes require “coins” to unlock. Lastly, the in-app purchase setup is very reasonable. The other thing I like about this game is that each time you play a scenario you are given a different subset of the objects on that scenario to find, so you can play the same scenario multiple times and it’s different each time. It’s not required that you get three stars on a scenario in order to play the next one. However, if you don’t care about those goals, you can just ignore them. To get the full credit of three stars on a scenario, you have to hit three goals: 1) find all objects within the time limit, 2) find a bonus object within a separate, short time limit, 3) find some number (I’m not sure how many) of objects in a short time (referred to as a “frenzy” in the game).
It is timed, but unlike all the other hidden object games I’ve tried, when the timer runs out you can continue to play and search for as long as you want. This game is great, it is pure hidden object searches, no storyline or mysteries or puzzles, just lots and lots of hidden object searches.