I'm actually more interested in why it costs that kind of money to file for election? Seems it's not even a deposit? How can that be constitutional in any democracy? Pretty perv.
The fee is 1% of the salary for the office, assuming a candidate wins and serves the full term. A candidate could always go the petition route, which for a statewide office in South Carolina is 10,000 signatures. The requirement for a petition candidate for any office is 5% of the registered voters eligible to vote for an office, with a cap of 10,000 signatures, which comes into play with the Statewide offices, Congressman, some of the Solictor districts and countywide offices in the three largest counties of Charleston, Greenville, and Richland.
U.S. Senate has the highest filing fee of any office on the ballot this year, since it has a 6 year term and the highest annual salary. If he'd chosen to run for the S.C. House, he'd have only had to pay a $208 filing fee. Least expensive filing fee this year was for Anderson County Council, $178.60
Also, for parties that choose to nominate by convention instead of a primary, their candidates don't have to pay a filing fee either.