Make sure that you try both ALSA and MDA loan closets, Liz, if you have both available in your area.
Additionally, see if your state has an assistive technology program or agency that also deals with computer assistive technology and AAC (assisted and augmented communication). The ALSA or MDA social workers should be able to tell you that answer, but it won't hurt for you to do some looking for yourself.
Finally, if your PALS is on Medicare/Medicaid/VA, those agencies may pay for an eyegaze system, but you'll need a doctor's prescription for it.
As Tokahfang says, there are further alternatives that be used. The ALS and MDA reps should be able to get you started on the right path.
Best of luck to you and please let me know if there's anything I can do to help.