APA Divisions and APAGS give small travel funding awards and larger awards and grants. Your department and uni probably give some too. And, external agencies fund as well. Do some google searches--the funding opportunities you have would depend on your area & population of study.
JockNerd made some great suggestions. In doing your searches, keep in mind that many programs disqualify certain types of outside funding/income if you're on a departmental assistantship or fellowship. These disqualifications are sometimes relaxed during the summer term, though, so if nothing else, you could pick up a part-time job from May through August, should your program allow it.