Parents may think the expensive part of back-to-school season ends once the backpacks are packed and the first-day photos are taken. Then September arrives with activity fees, lunch charges, replacement supplies, club dues and requests for money that never appeared on the original shopping list. Those overlooked back-to-school expenses can turn an already expensive season into a month of budget surprises. The challenge is that many costs do not become clear until teachers, coaches and school organizations settle into their routines. For families trying to keep spending under control, the first month of school can be an important financial reality check.