Most schools I've seen the numbers on have maybe a $3 markup, and fewer than 100 students, with about half of them testing about once year, the rest averaging 3 tests a year. Yes, shirts and such do have more, but that's not related to testing. Uniforms usually carry more markup (I sell mine at wholesale, rounded up to cover shipping), but most students won't buy a new uniform for years (in fact, most students will quit before they wear one out).They buy at wholesale and sell at retail Generally it's a $3 or $4 markup, so $4 x 4 (tests per year?) x 100 students = $1600 per year? / 12 = $133 per month extra revenue...and I bet the mark-up is more...combine that with shirts, special uniforms, seminars, etc...$$$