Just deleted a game, 'running with friends' from my ipad. Free to play but with a deeply cynical in app payment system that you have to buy more and more gems otherwise you cannot beat others. There is no offline version so you are always competing against another person and therefore need more gems than you can win by playing well.
Too many aspects of education and life are now the equivalent of these in app purchases. Years ago I convinced my then boss to invest in three subscriptions to 'real robots' which through weekly magazines built up into a real programmable expandable robot. After 18 issues and with three partly built but non functioning robots later, it was clear the publishers were being economical with the truth and in fact it would need another 12 issues to complete and then another subscription to add the features we were told were included within the initial 18 issues. Ate humble pie, apologised to my boss and we scrapped the lot.
Many schools are part of larger organisations that often 'prefer' their own curriculum model. These are cited as being better than the stamndard and come with shiny books or acres of presentations. Unlike a bike or a robot, it's devastating to scrap a curriculum half way through, especially if the philosophy it's based on is very strong. Beware if you a signed up to one of these 'all in one' versions. Government policy or the law or student rights may change swift,y and leave you having to pay more for the update than it would have cost you to write or pay someone to write your own. A good point to consider is whether the 'color' of your curriculum matches your local circumstances. If jimmy plays baseball, and his maths worksheet is based on it, james may flunk a test based on the worksheets teaching, and that's just not cricket....