Most of the times we see giveaway contests or rather internet competitions held by people on social media or personal websites, where the winner gets some prize if he/she wins with no cost to the participants. People who enter the competition will either gain something or at least will be safe and sound, and that no one will lose to anyone or anything?
The ruling for this is that there is no wrong in taking part in such competitions wheather held on the internet or elsewhere if the participants or entrants do not lose anything and will be safe and sound after the competition then it is okay as it does not involve gambling.
Gambling means something that the person does not know if he will win or lose and if he will gain or lose something. In gambling, there is a risk or losing something that is valuable to the entrant. In such competition often the participants are not at the loss even if they don't win it. It makes no difference to them.
However, care must be taken in participating in competitions that are contaminated with haraam things such as music or other things that are not permissible in Islam. If it involves any of that Then in such a case it becomes harAm. Not because of gambling but the things that it deals with.
And Allaah knows best.
May Allah guide us in all aspects of our lives and protect us from all evils and doubts. May He, the exhalted grant Jannat ul Firdous to all muslimeen.