If you will join single bounty then for sure thats a cheaper amount but since you offer Twitter and facebook services so you can join as many as you can so the payments can be maximize,only signature campaign  is required signature and avatar wearing mean you cannot participate in other  signature projects.but since you are a newbie its impossible for you to participate

But also you can offer video services or blog creating ,since these are the highest paying works in bounty nowadays,but ofcourse this require skills and knowledge so goodluck