I have two feather dusters in my 9 gallon tank. One is the brown and the other is a lime green color. I can't remember exactly how much they were each but, I think it was like nine dollars. They are both doing great. I've had them since March of this year.
If I can keep them alive in the nano, anyone can keep them alive.
these are the two that I have...
the first one is the hawaiian and the second one is the green/yellow.