If anything, $13 is cheap.
You haven't stated if you want AMOLED or PMOLED. If monochrome, you may get away with PMOLED, but these tend to have pretty bad ghosting on the image, so only really useful for control interfaces, text, etc. For greyscale graphics, forget about it, you almost certainly need AMOLED.
A cheaper OLED will also likely be overdriven at high brightness and have a short lifespan. We've seen as short as 1000 hours from some displays before they're burned in so badly that they are unusable. And those are $300 parts, though micro-size type.