Dot.com millionaire Jennifer Sultan has now gone from the penthouse to the poorhouse to the big house.

A Manhattan judge yesterday wrote the latest chapter in Sultan’s riches-to-rags tale, promising a four-year prison term for a guilty plea to charges of gun conspiracy and drug sales.

Sultan, 38, was caught texting the ringleader last June about a .357 Magnum and was snagged on wiretaps discussing firearm prices.

With good behavior and time served, she could be out in less than two years, her lawyer said.