Well, the ad is a bit unclear on one point: It reads at one point: Get this care package started and are joined by a load of hot tamales and atomic fire balls. So my first question is, "Does the care package contain tamles and fire balls?" (If so, that might explain the $23 care package tag)
(If it doesn't, then your question wouldn’t it be cheaper for the missionary to buy his own bag of tostitos and dip is more likely simply a practical issue than a cost issue. What do I mean? First of all, many LDS missionaries are in remote areas where a purchase of this nature simply isn't possible. Secondly, even if these items could be purchased by them, LDS missionaries don't necessarily have the "cash on hand" to be buying snack items. Finally, their lives are pretty much scheduled for them 16-18 hrs. a day & the rest is pure sleep time...so on some weeks, even getting to a store to make such a purchase wouldn't be a sure thing... So, care packages are a "way of life" for many LDS missionaries)