First, I want to mention, that by time you can trap a dragon and take his soul to sell it, a 1000gp will not be that much wealth to your "hero" anymore.
As a GM, I wouldn't allow you to create such a character UNLESS you can convince me why this would be fun. For you and for the others and for me. You have to provide a reason, why your group would want to work together instead of killing you on sight. And don't only rely on hiding your alignment, because that will not work too long. Also, it might be much more fun, if they KNOW about your alignment, but other circumstances force them to work with you.
Also, playing such a char just for beeing able to "farm gold with demons" is not very interesting. Also, just because you are evil too, doesn't mean they like you. Heck, they would kill and eat their own mother if they could, they don't have an evil alignment, they ARE that evil alignment.
You are going to experience adventures. Of course, you can also try to build an evil wizzards tower etc., but is this really what you want to do all the time in the game? Why do you need the other players for that?
But instead of only giving critical questions, I want to contribute a couple of ideas for your character:
What about playing a chaotic neutral character, who is just very curios and is interested in daemons? You don't need to be evil for this, you can even accept good deeds, but you are not as extremistic about playing with devils if this makes sense and is interesting. It would also lead to a lot of discussions between your group members, but they don't necceserely have to end into a battle about life and death.
The other idea would be, that you play an really evil character, who was send by his god to turn the good aligned heros around. Who tries to justify evil and make them do evil things. And the others heros have similar things in mind, they want to "cure" the evil that is within you. But actually, I don't believe this is going to work, unless you all don't really give a s+$! about your alignments when you roleplay your character (which is totally ok, if this works for you).
My current group is Good/Neutral, but on their way to save the city from a Leukodaemon, they already murdered a couple of innocent people, who where just doing their jobs (guardsmen).