I bought aftermarket tow mirrors
like these for my Tundra. In a side by side comparison with the OEM you couldn't tell the difference. Fairly easy to install yourself. I just sold them when I traded my truck in. Got almost what I paid for them back. Keep an eye on the forums too (tundratalk, tundrasolutions), you'll see oem ones in the classifieds once in a while.
That being said, $600 installed for OEM doesn't sound that bad. Dodge wants $800 EACH for my new truck mirrors, PLUS installation. Ill be going aftermarket again.