I'm not a health major, but I'm guessing statistics will be slightly more useful to you.
Which saves the most money? Odds are both classes are the same number of credit hours, so neither will save you more than the other. In fact, depending on how UCSD charges tuition, they may not save you any money at all.
If UCSD charges tuition per credit hour, and if they accept AP credit for those subjects, then you'll save money.
However, if they charge tuition per semester, then the only way you'll save money is by getting enough credits to graduate early.