Photo Contests: Draws and Judgings
Some contests are random draws (RD) and some are based on image quality/artistic merit (AM).
The A-M ones are good for building your skill, as most of them provide feedback even if you don't win.
Some of the artistic-merit contests charge an admission fee.
On the Random Draw side, a lot of big and small photo companies give away gear for free.
Of course it's not totally free; it's a way of building their
mailing lists, which helps them reach potential customers.
Kind of win-win.
Where the expiry date is not shown, it's a recurring contest.
ViewBug and Android Authority change very frequently;
the bigger names are annual or even every two years (Nikon).