The sale of any food or beverage by a vendor (whether incorporated or not) for use in a candidate's campaign, or for use by a political committee of a political party, at a charge less than the normal or comparable commercial charge, is not an expenditure, provided that the charge is at least equal to the cost of such food or beverage to the vendor, to the extent that: The aggregate value of such discount given by the vendor on behalf of any single candidate does not exceed $1,000 with respect to any single election; and on behalf of all political committees of each political party does not exceed $2,000 in a calendar year.