Most bloggers today offers give away of many kinds ranging from premium video creators , plugins , software and many more .

I wanna find out more about those give away , are they usually sponsored by a company , or do the blog owners just decide to share them to get one or two stuff and finally do they have full legal right (written permission ) to distribute them for free?

Sorry for my being too inquisitive , I'm only showing I'm a novice in this kinda stuff