We booked our holiday in early January with Budget Travel and availed of the Budget Sale. Three air fares (two adults and one child) and accommodation with transfers and insurance came to £1,180.
Shop around for any tours you intend to take. Prices vary considerably. Our day trip to Chichen Itza was $35 each - and included lunch.
Everything can be negotiated - meals and purchases. Tipping is essential. Prices downtown are much cheaper than the hotel zone.
The ferry for Isla Mujeres goes from Puerto Juarez and costs about $1.50 for the slow boat, and $3 for the fast boat. The water taxi cost roughly $12 per person. We were about four hours at sea - snorkelled, swam with sharks - great value. The golf car cost some $12 per hour.
To get to the we took a coach from the bus station in Cancun to Playa Carmen. This cost about $3 each. We then took a taxi to Cenote Azul. This cost about $15 for three.