I found some ads listing Bell System toll rates from New York City (Manhattan) to various points.
By way of comparison, bare bones service from Verizon offers long distance anywhere in the U.S. for 12c per minute.
By 1930, long distance was an established process, with specially designed switchboards, routings, and repeater placement. There were subsequent rate decreases.
After WW II, dial direct, coaxial cable, and microwave all allowed greater economies of scale, allowing further rate decreases.
Bell System Long Distance Rates effective Dec 1, 1927 station to station, first three minutes.
From Manhattan, NYC. Evening rates cheaper.
LawrencevilleNJ 0.45 Albany 0.90 Pottstown PA 0.70 Washington DC 1.20 Syracuse 1.30 Pittsburgh 1.70 Buffalo 1.90 Cleveland 2.05 Detroit 2.30 Louisville 2.80 Chicago 3.25 Atlanta 3.25 St. Louis 3.50 St. Paul 4.00 New Orleans 4.50 Denver 6.00 San Francisco 9.00 Great Britain 75.00