Block Foreign-Funded Political Ads Act This bill requires certain entities (i.e., television and radio broadcasting stations, providers of cable and satellite television, and online platforms) to make reasonable efforts to ensure that political advertisements are not directly or indirectly purchased by a foreign national. Specifically, the bill requires these entities to directly inquire whether the purchase for a political advertisement is being made by a foreign national. It also requires these entities, when accepting a credit card purchase for a political advertisement, to collect the credit card's verification value. The card's billing address must be in the United States unless the purchaser is a U.S. citizen living outside of the United States, in which case the purchaser must provide his or her voter registration address.