Free Giveaway: This the far most used scam by companies. There are some legitimate giveaways, but they are very few and far between. Apple/Microsoft does not really like giveaways using their products and have rather stiff guidelines about them, including a restriction that "free" not be used prominently in any display of the giveaway, so anytime you see "Free iPad" posted in bold letters, you know it is a scam. But be caution, most of other gadgets giveaway are scams.
The best option to avoid these scams is to simply don't participate in this giveaways. But sometimes you get believe that a giveaway is legitimate because its from Known company. so always directly got to companies website. Do not click on a link from an email, Facebook update or Twitter tweet no matter how official it looks.
Test the product and Get free iPad (any gadget): A nice variation of the iPad Giveaway scam is the offer of a free iPad after doing some type of testing. The testing could be on an app -- including apps for popular websites like Twitter or Yahoo -- or on an expensive accessory. But don't be fooled. This is just another giveaway scam wrapped in a slightly different package.
In-app Purchases: It isn't much kind of scam but it holds your money without knowing it, especially when buying accessories for a free game inside the app. Game is free to play but in-app games accessories purchasing are not free.
