Nice design. Actually with that design you can offer your skills on here to design/create a signature for any project (ussually campaign).
You are also can participate in any of signature design contest but this is rarely happens.

From all packages (jr.member - legendary) ussually it would be around 0.1 - 0.2 btc.

I have seen this on Micro Earnings section at GameOfBitcoins thread, really nice, you have professional skills.

Even you don't want to charge money for your job now, don't forget to ask for donations, put your BTC address in public, people usually reward artists like you if there isn't a payment agreed. I'm sure you are very able to earn money from it.