This is something students always bring up sooner or later. They hate the idea of renting without building any equity. Yet, as we all know, the fixed costs are often times the real killer when it comes to private aircraft ownership. Years back, when I was doing the mechanic thing, we had a Baron we used to do the annual on. It flew maybe 5-10 hours a year if that. The insurance, hanger, and maintnence costs must have eaten the owners alive.
The problem of course is that only a few people, other than actual owners truely know what the fixed costs, and total operating costs of an aircraft is. That is, until the advent of the sharing information on the internet. I found a really cool site PlaneQuest which allows you to select an aircraft, and view a composite of both fixed and operating costs. While the numbers seem biased a little bit low imho, they still serve as a reasonable ball park figure to help your students make the right choices.
My guess, is that the maintenance figures are based upon owners assisted annuals, and good old boy discounts. Insurance for anything other than a 150, 172 or warrior as usual borders on extortion, as do hanger costs, depending where one is located. Thus, depending upon ones insurance risk, and location, the total costs may be pretty decent. No matter what, it will help a student understand some of the costs involved.