Will attending EPGY get you into college? No. But no summer program will (except RSI).
Attending EPGY will show you are interested in a particular subject and in learning which colleges value. I know for me that attending EPGY along with many other extracurricular activities showed my interest in learning and desire to learn more about various subjects I was interested in. However, EPGY is not very selective to get into so it is not really a stamp of approval. Also, due to the price, colleges don't weigh it against students who do not attend EPGY or similar camps.
As I hinted at above, I spent two summers at EPGY. The first summer was amazing. It was fun, informative, and I met a lot of awesome people (still in touch with many 4+ years later). The second was still a good summer but nothing could match that first summer. In terms of being worth the price, that is hard because you have to ask yourself what you want out of it and your family's ability to pay. There are many other ways to achieve similar results in terms of learning but what EPGY has going for it is a fun collaborative environment. Also, EPGY does offer some financial aid.
I hope this answers your question.