Most programs consider applicants on a holistic basis; if you have low GRE scores but make up for it in another area (i.e. LOTS of research experience, great recommendations, etc.) you may still have a chance at getting in. This is my third application cycle and I've retaken the GRE each year, scored higher, and then still haven't gotten in (on top of having high undergrad and masters GPAs, good recs, and 3 years experience in an experimental psychology lab). Seems to really be a case by case basis! Don't give up hope, it takes most people multiple application cycles to get an offer.