You wont need to start with a dedicated obvisously. Start with a $10 hosting package from a reputable shared hosting company, As your site grows your next step will be a VPS which for good ones run anywhere from $50-100 a month, but at that time, you're site should be generating some revenue to offset that cost.
Once you get to your goal you'll need a dedicated server, Right now i am using a Dual core, Dual processor woodcrest with 6GB ram, 1TB disk, and 2000GB of bandwidth and is a considerable amount under the 800 mark and it powers my site with ease, and creates plenty of room to grow greatly