A looong time ago, I won a Lamy Joy Calligraphy fountain pen 1.1mm from JetPens. They also sent along two Kuretake Brush Writers - one in black and one in silver. They currently have similar brush writers though I suspect newer models - and they're on clear out! So I highly recommend you pick up a few!
After I first "reviewed" them, I wasn't sure how to use them so I kind of stuck them in a box for over a year. Guess what? They haven't dried out one bit. Super awesome. I also had a Pentel Metallic brush pen I had bought in undergrad so it's a good.... well. It's old. I don't want to give away my age here. I took these three brush writers and made some doodles with them!
Pentel Metallic Brush Pen - $7.90
Kuretake Brush Blendable Brush Writers - $7.00 at JetPens