Check out Mesechta Beitza 16a:
“The entire sustenance of a person is fixed for him from Rosh HaShana until Yom Kippur, except the expenditure for Shabbosos, Yomim Tovim, and the expenditure for the instruction of his children in Talmud Torah. If he spent less he is given less and if he spent more he is given more.”
So you have a havtacha from the gemora that, even if you pay full price for matza, you won’t lose.
Chag Kosher V’Someach!