Bytes are an item used for subscribing, motivation production, or a ID change if you have enough of them. There are several ways to get them:
You can buy bytes directly from the game at the Finance Office, located in City Hall on Georgetown's Government Row. Bytes cost $8USD for a pack of 100 and you can buy as many as your heart desires.
You can use credits to buy bytes from other players in the Marketplace.
You can get bytes for free in the Earn Bytes section. You'll need to fill out some forms and surveys, shortly after bytes will be credited to your account.
You can earn a byte through random encounters by guessing the correct lollipop!
Once you have bytes, you can...
Sell them at the Marketplace to make a large profit.
Take 70 bytes to the Finance Office and buy yourself a month of subscription time.