I started experimenting with Woocommerce, and decided to create a proof-of-concept for a micropayments-based wordpress blog, too.
In my woocommerce, I have 3 virtual products that are displayed at the bottom of each page; "Liked it!", "Loved it!" and "Saved my life!". These products have different price, of course, "insanely cheap", "cheap enough" and "starts to look like an amount".