Who pays for the primaries?

[Parasite]

In the UK we have no primaries - although parties may organise their own equivalent of "primaries", which is to gather all the voters who deign to register to vote in the "primary" in a constituency in a church hall or school assembly hall one quiet evening, and have them select the party nominee. It's not a primary in the American sense.

Otherwise selection of nominees is restricted to party members, and party membership consists of paying the equivalent of $40 or $60 a year to the central party or the district party.

Hence, all the cost devolves on the party, but this cost consists of renting a hall for 2 hours. In the US the state-wide primary system seems to be an ingrained part of electoral procedure and, unless state parties repudiate such a procedure, it seems fair that the cost should fall on the state.