clearheaded:
Working with the same logic, it is not how much you spend on the milestone, but the relative importance you place on it (which includes treating it respectfully).
No one (except maybe two+cent) would consider having water for a Siyum Mesechta, one should have a Chashuv Seuda. Having water for a siyum shows your disdain for the accomplishment, and a similar concept applies to other accomplishments (such as becoming a “Bar” Chiyuva), or starting a bayis Ne’eman B’Yisroel (excluding the simchas Chatan V’Kallah aspect).