Check out The Golden Sunset (across the road from Alfreds) which is owned/operated by Ray Arthurs. The Arthurs family, which also includes Alfred, are one of the original Negril tourist pioneers. Golden Sunset has great rates and many repeat guests. http://thegoldensunset.com.
Another hotel in that area with great rates is Hidden Paradise.

August 1st is Emancipation Day in JA and August 6th is JA's 50th Independence Day. ATI is on August 3rd-August 7th. ATI is a wild weekend in Negril as people from all over Jamaica converge for 4 days/nights of parties, and most hotels will already be fully booked for those dates (at premium rates). ATI attracts mostly young adult Jamaicans who want to party with special events planned on all days/nights.