A standard post office box, or really any mailing address, and a US dollar money order sent in the mail - old tech that works, cashable by almost any bank. Certified checks drawn on major banks work almost as well.

Setting up a bank account can offer direct wire transfer as a third method, but the money order is almost impossible to interrupt.

Good old bullion (silver or gold) is also acceptable for tax free mailing in many locations - but you have to confirm the local rules first. Again, while the price fluctuates, it has the advantage of being convertible to cash nearly everywhere.

The powers that be have no idea how dangerous it is to force sites like Voat to operate in the cash economy. Once the technique is learned it becomes very apparent that banks are no longer needed for free commerce.