The Federal Election Commission classifies gifts of goods and services (including advertisements) offered for free or below-market rates as "in-kind contributions." The limit on individual campaign contributions directly to a candidate's campaign is $2,800 per election. Thus, any in-kind contribution from an individual over this threshold would violate the individual-contribution limit.
Under FEC rules, "independent" spending in favor of (or against) a particular candidate is not restricted, provided that it is not coordinated in any way by the candidate, campaign committees or agents of a political party.