3x3 serves about 4 people? Are these centerpiece cakes, that will be on a table with only 4 people per table? (hate to see them try to divide this up amongst the standard 8-per-table.) Or is she giving a cake to each person?
Here's a similar thread with some add'l info: http://cakecentral.com/cake-decorating-ftopict-663818.html
Smaller cakes are more work. 65 cakes that serve 4 people = 260 servings. I can make a 260 serving cake in 5 tiers .. that's 10 pans to prep, bake and wash. 65 3" cakes are 65 pans to prep, bake and wash. My 5 tier cake will use 5 cardboards. Your 65 cakes will use 65 cardboards and boxes.
My rule of thumb: 1/4 the size means 4 times the price.
Styro's or fake cakes are not close to free, like many brides think. Here's my blog article that explains why: http://cateritsimple.blogspot.com/search/label/fake%20cake
If were to take this order .....
260 servings x my $3.50/BC serving price = $910 plus the added PITA/labor/materials/setup fee of $390 = $1300. Delivery would be extra, depending on the location.
a 3-tier fake cake ... 6/8/10 round, serves 74 x $3.50/serving = $259 x 80% = $207 + 1300 = $1507.
Or she could have a grand 5 tier cake for $910.