But Mr. Castro’s early tinkering has already laid bare an uncomfortable, and potentially destabilizing, reality in a country that for 50 years has been run as one of the world’s most rigid socialist systems: that some Cubans are far better off than others, whether because of remittances from relatives abroad, ties to the ruling class or unauthorized money-making ventures on the side.

Image Cubans in Havana recently bought DVD players, among newly available appliances. Credit... Jose Goitia for The New York Times

For now, his government seems willing to accept those disparities, tolerating the notion of class differences while continuing to cling to a Cuban vision of socialism that includes food subsidies, free education and health care for all, Mr. Castro’s backers in the government say.

Whether that approach will satisfy Cubans, who are quickly becoming more aware of their relative consumer deprivation, is another question. A rice maker alone costs more than three times the average monthly state salary here. Conversations on the street, away from the lines of people buying what is newly available to them, reveal discontent.

Javier, a 25-year-old computer programmer, has made up his mind to leave Cuba for California as soon as he can. “Come on, these changes are only in favor of a very tiny part of the population,” he said, sitting along a coastal wall and staring into the ocean. “We, who get up early in the morning to get the bus, we, who have sacrificed ourselves, we can’t afford all this,” he added. “I’d love to go to a fancy hotel with my girlfriend for a night or two. But, hey, I simply can’t. I couldn’t afford it, even in my dreams.”

Even for those who can, it is a journey into another world that was all but off limits just weeks ago. The other day, a young woman struggled for 20 minutes to get into a Havana hotel room, jamming her key card in the slot haphazardly and shoving the door with all her might. She could be excused, though, since it was her first time using such a contraption. In her case, her foreign boyfriend paid the $175-a-night bill.

“Different classes have always existed but they are more visible now,” explained María Ileana Faguaga, a Havana-based anthropologist who specializes in Cuba’s struggling black population. “Now you just look at who has a cellphone.”

A taxi driver barreling along the seaside Malecón, who like most Cuban workers is paid by the state, pulled out a Nokia from his pocket this week. “This one has a camera and Bluetooth,” he said, boasting that he was one of the first in line when Mr. Castro recently ended the restrictions.