Good question! A couple results I just uncovered through Newspapers.com:

Per an October 1982 article in the Miami News, about 30 percent of the city’s OnTV customers—of which there were around 45,000 at the time—bought Star Wars. That percentage was actually significantly lower than those that watched a pair of boxing matches the year prior, but on the other hand, OnTV may have had a slightly larger audience at the time than it did at launch.

And an article during the same month in the Pittsburgh Post-Gazette said that 185,000 people nationwide bought the movie at a price between $7 and $8—also a 30 percent buy rate. At that number, the film made between $1.3 and $1.5 million in revenue (with inflation added, between $3.4 and $3.9 million today); no word on the profits, however, but not bad for a single showing of a movie in 1982 on a pay-TV system that was only available in a few major cities.