Historically there were restrictions on voting that no longer exist: being white, male or property-owner are examples. For example, the 15th amendment prohibited denying the right to vote on the basis of
race, color, or previous condition of servitude; women got the right to vote under the 19th amendment; poll taxes and a requirement for paying any other tax were abolished by the 24th Amendment (this did not address state elections). In the case of property ownership, the property requirement was eliminated state-by state by 1856. Tax-payment was a requirement for a longer period, but again was abolished state-by-state.
Later, in Harper v. Virginia State Board of Elections, 383 U.S. 663 SCOTUS ruled that
a state violates the Equal Protection Clause of the Fourteenth
Amendment to the U.S. Constitution whenever it makes the affluence of
the voter or payment of any fee an electoral standard. Voter
qualifications have no relation to wealth