The SIGPLAN professional activities commitee has limited travel support available to help some attendees attend SIGPLAN events.
Students in need of travel support are encouraged to apply.
For more details, see: http://www.sigplan.org/PAC/Main
In addition to the regular PAC funding, US students are eligible for travel support from the National Science Foundation.
Applying for NSF support is straightforward, by simply filling out the “Funding from other sources” section on the PAC website as part of your regular application.
Finally, PLDI has a Student Volunteer Program for more information on the Student Volunteer program, please see https://conf.researchr.org/attending/pldi2015/Student+Volunteers