I graduated fewer than 5 years ago and know that it is certainly NOT the case that PTS offers most MDiv students full tuition at least, as implied above. With a few highly selective exceptions (merit scholarships and the like) that do offer tuition + stipend, almost all MDiv tuition grants are need-based and adjusted every year. More than a few of us received full-tuition grants our first year in the MDiv program only to see the grants decline steadily in each successive year. And if a partner/spouse works, it can be hard to demonstrate need given the relatively high wages paid in NJ, despite the fact that cost-of-living is so high. So just because one is offered a free ride going in does not mean that ride will continue once they've got you in the door, unless it is so stated in your offer letter. Also, some have suggested that the PTS president (installed 2004) wants to see tuition grants to non-Presbyterians reduced even further.
All that being said, even if one is only awarded a meager grant, PTS's tuition is still insanely cheap ($10K or so per year) compared to its perceived peer institutions.
FYI...