Playa Larga is an unremarkable beach in the south of Matanzas province of Cuba. It is interesting mainly as a convenient stopover on the way from Havana to Playa Giron beach. Shore and seabed: sand. 
Horizontes Playa Larga Hotel Matanzas is the best hotel on the beach. It's located in the best part of the beach - in the east end. Room rates starts from $75 per night.
The west segment of the beach has no real hotels, but there are a lot of Casas Particulares. This is the Cuban way to call family run guest houses. In most cases, you don't have to pre-book these casas.