Pixlr-o-matic for Android (screenshots)
Free filters, effects, and frames for your Android photos.
Pixlr-o-matic start screen
Unfortunately, you can only apply one filter and you can't increase or decrease the effect. The only way to apply additional filters is to save out and reopen the photo. That goes for all three. Also, all of the color filters have nondescriptive names, making it a pain to quickly pick your desired result. For example, Sophia is apparently heavy vignetting typical of a toy camera lens.