Anyone who can legally own a property in the United States may buy a tax lien. These tax lien sales are conducted by the county and winning bidders can pay by cash either on the spot or within 48 hours. Before the schedule of the sale, there would a pre-registration for those who want to join the bidding. Also, there are rules to be observed which may vary from state to state.
Investing in tax liens is best done locally which may take a lot of time, labor, and money out from you. You can acquire a list of available tax liens from the county office for a fee, or do your own research online to get them for free. That is why due diligence is expected from this lucrative investment.