I tried to have things available at varying prices, because I know people can't always afford to spend a lot on things like this. So far I have:
A wallpaper at Lulu.com: you get all sizes (800x800,1024x768,1280x1024, and 1600x900) for $3!
And some cute things at CafePress.com!
A greeting card for $5
A calendar-print for $7
A mousepad for $15
and shirts based on the "Bonk!" of strip #383
A t-shirt(dark) for $23
A t-shirt(white) for $19
A t-shirt(white) for $13 (this one is less because it's the "value" shirt, so the material is a little thinner; would make a good undershirt)
I tried to get a copy of the things to make sure they looked nice, before offering them for sale, but I didn't get the card or print yet, or the standard white t-shirt. But the mousepad, dark shirt and white undershirt looked cute.
If none of these options appeal, feel free to click the Donation link on the front page and Send Me a Dollar!
Or if you're looking for non-financial ways to support the comic, just keep reading, tell your friends, talk on the forums, etc! You are all awesome, whether you can donate or not!
