Sadie is a princess who loves dancing, cries at the drop of a hat, and has found herself imprisoned in a tower with a pudgy dragon as her sole companion—that is, until the unicorn riding, butt-kicking Princess Amira shows up to rescue her and throws a wrench in their fairytale story.
Strangely Katie's Princess Princess is a self-contained webcomic story about two very different princesses who end up defying fairytale conventions. Instead of marrying a prince or waiting around in a tower, the decide to go off on their own adventure—but not everyone is happy about this little escapade. And it's not just princesses who have to fight against their genre expectations; there are princes who want something different from their lives than the acts of heroism their parents expect from them.
And if you like Princess Princess, I highly recommend you also check out Princeless, Jeremy Whitley and M. Goodwin's comic series about a princess who grows weary of her captivity and goes on a quest to rescue each of her sisters from their respective towers.
Princess Princess is free to read online, but you can also purchase the comic along with an epilogue and high-resolution artwork through Gumroad.