Per the US Department of State website:

On March 3, the Venezuelan Embassy in Washington, DC posted updated tourist visa information for U.S. citizens planning travel to Venezuela. According to the website of the Venezuelan Embassy in Washington, U.S. citizens should plan to apply for a visa three months in advance of travel. U.S. citizens should expect to pay $30 for a one-year, multiple-entry visa good for a 90 day stay in Venezuela.

All U.S. citizens planning travel to Venezuela must have a tourist visa. The U.S. Embassy in Caracas is aware that airlines have refused to board U.S. citizens who do not possess a Venezuelan tourist visa. The Embassy strongly urges all U.S. citizens planning travel to Venezuela to check both the Venezuelan Embassy’s English and Spanish webpages regularly for the most up to date information about visa application requirements and procedures. U.S. citizens should direct questions to the Venezuelan Embassy in Washington, DC or Venezuelan Consulates currently located in Boston, New York City, Chicago, New Orleans, Houston, San Francisco, and San Juan, Puerto Rico.