Unironically my local library. May vary depending on where you live but many local library systems are pretty comics rich these days.
For a while I was enjoying going to small press conventions, which are a different sort of animal compared to mainstream comic conventions. What's available for cons/expos is also pretty dependent on where you live, unless you're willing to make the trek to a big name one like the Small Press Expo or the Toronto Comics Arts Festival. If you're willing to sift through a lot of muck for obscure gems, nothing beats an expo.
