I need a very cheap flight.?

Im living in San Diego right now, but I really need to visit my family back in England. I've been working my bum off and have got about a thousand dollars. I'm planning on leaving on the 21st of July, and returning on the 16th of August. Is there any way to get an extremely cheap flight so that I still have enough money for food and such? Thanks, and by the way, I'm 16.