I have found that the very basic, inexpensive plain-colored long-sleeved jerseys from Performance (their house brand) are very thin and wicking. This would seem to be what you are looking for, and at a reasonable cost. I have a white one and it would be perfect for a warm-weather ride, but I can't bring myself to wear it for that (I wear 30 spf, water/sweat-proof sunscreen and short- or no-sleeve jerseys and end up lightly tanned but not burned) so I mostly layer it over a base layer for cooler-weather rides.

Good luck!
Emily