The Yerfshop (link) is where avatar bits for use in the Avatar Lab and custom titles can be purchased. Purchasing avatar bits will cost you anywhere from 5-25 yerfbucks, but once purchased, they can be used as many times as you wish.
Avatar bits are separated into the following categories:
The Yerfshop can also be used to change your custom title. If you don't have a custom title set, your title will change as you make more forum posts. Custom titles can have a maximum of 30 characters, but only using letters, spaces and the following symbols: ( ) * ! # $ & % . , : ; ? " ' HTML, BBCode or other codes also won't work for custom titles. There is no way to get a refund on the 25 yerfbucks you spent purchasing a Custom Title, so make sure there aren't any mistakes!