Reply to Help, Beach party problem!

Hey guys, I don't know if this is the right place to post this because I'm new here but hopefully somebody will see this and can help me. I'm going to be spinning on the beach next week and I'm trying to figure out a cheap solution to get power. I don't need much power ( running Macbook, S2, and 150w speakers, 150w sub) I know I can rent a generator that runs on gas, but I was looking for a different solution then that. Anybody have any suggestions? Maybe a battery powered source?