Yes, after every so many Alliance Points/AP that you earn, you'll get pieces of gear sent to you for your current level.
Usually each piece is different, so it depends on what you're using and what you need to become better geared in PVP.
A lot of times the gear sent in rewards are worthless and you won't even use them. But it's free!
Generally these are only good if you are leveling faster than you're obtaining gear. They are all green pieces, however can come in handy for a nice filler or to strengthen you up a bit when leveling.
The really good rewards come from at the end of the campaign.
These will as well, be mailed to you in game.
If you get top 2 or 3 % on the leaderboards, expect a gold item or even a few.
You'll also get s decent chunk of change too, like $10-20k.