NEW YORK ( MainStreet) — In different times, it wasn't unusual to pick a school because your mother or father went there. More recently, cool schools were sought after that led to a gig in an upstart industry—tech, media, pick your favorite.

Now it's more about what this is all going to cost.

According to a study released yesterday by the University of California's Higher Education Research Institute, the cost of college and the availability of financial aid that will defray it is becoming the biggest influence on school choice. At the same time, colleges are worried that tuition discount rates that are drawing students to their campuses are quickly becoming unsustainable. Discounts and deals, scholarships and institutional loans vary from school to school. When and if the crack up will begin and whether it could happen slowly or all at once is anyone's guess.

In 2013 the largest number of students on record were not in their first-choice college. The Cal study found that only 57% of freshman at four-year schools went to their first choice, although 76% got acceptances at their preferred college. The rest went to fallback schools.

Ten years ago, 69% of freshmen went to their first choice school. In 1993 it was 72%.

Among freshmen who had been accepted by their first-choice institutions but enrolled elsewhere this academic year, 60% said their current college's offer of financial assistance was a very important factor in their decision. 62% said the cost of their first-choice college was very important; nearly 25% cited a lack of financial aid as a reason for going elsewhere. The Cal report said that in 1973, 19% of students said financial aid was very important.

Kevin Eagan, interim director of the Cal research program, told the The Chronicle for Higher Education , "Students are becoming savvier shoppers, in part because of the national conversation about rising student-loan debt. They are, he added, "searching for the best package" and the best deal.

Academic reputation rated with 64%; prospects for a job after graduation were important to 53% in making their decision. But nearly half of freshmen this year put financial aid first on their list of must-haves — which may say something about what they expect from the job market.

Among students who are the first in their families to go to college, financial factors have even more clout. 54% of first-generation students said the cost of attendance was very important in choosing their current college, and more than 60% said that of financial aid.

A greater share of students in four-year public colleges (54%) compared to those in four-year private colleges (39%)said cost had been very important in their decision. But more students in private schools than in public schools said financial aid was important-- 65% compared to 42%.