Newbies should never be allowed for bounties because there is nearly no protection against spam and multiple accounts per member.
Most of the newbies are used for pumping ANN threads and aren't even adding good points to a discussion but I'm not generalizing, I said most of them but there are still some few ones that's adding good contribution to the discussion.
There are some bounties that are still allowing newbies even the signature space is only small for that rank since the reward isn't that expensive for them.
The first thing you should do is raise your rank to Jr. Member
Jr members does have the same signature space to newbies now.