When I look at free games on the App Store I see if it says "offers in-app purchases". If it does I look at the in-app purchases. If the in-app purchases are "x00 Special In-Game Currency Units" then I don't install the game. Not sure we need legislation to avoid being ripped off...
Which is something I find interesting: people talk about "discovery" and reviews of apps being difficult. You're on a device that's sole purpose is internet connectivity! Use the browser, Luke!