11 CFR §100.79

1. (a)Transportation expenses. Any unreimbursed payment for transportation expenses incurred by any individual on behalf of any candidate or any political committee of a political party is not a contribution to the extent that:
   1. (1)The aggregate value of the payments made by such individual on behalf of a candidate does not exceed $1,000 with respect to a single election; and
   2. (2)The aggregate value of the payments made by such individual on behalf of all political committees of each political party does not exceed $2,000 in a calendar year.
2. (b)Subsistence expenses. Any unreimbursed payment from a volunteer's personal funds for usual and normal subsistence expenses incidental to volunteer activity is not a contribution.