Actually, if you just buy stuff, you have a Buyers Account which is not the same as a Sellers account. eBay bases a lot of their opinion of your selling status after you actually sell stuff but buying stuff is a nice way to get your number a little higher.
I can tell you how to get a lot of feedback and profit a little. Find a couple big sellers from Hong Kong, China, Taiwan, or Singapore (which has the cheapest cost for international mail), find out what they are selling the most of on a daily basis, find the same items' value being sold by a seller in your country. Buy x amount from Asian seller to get a discount, get your items, and resell them individually. Its best to buy enough just to resell within a month.
If you dont mind taking a financial loss (but you will look good to eBay) - buy a bunch of crap people will buy from your nearest dollar store. Resell online.