When buying clothing to sell on eBay, be sure you have the right sizes in your business inventory. The average American woman’s dress size is 14 (the beginning of plus size clothing), not an 8 and the average American man is a 40 regular. When buying apparel for your eBay business in lots for resale, ignore the standard “1 small, 3 medium, and 2 large” lot, and instead buy 1 small, 2 medium, 1 large, and 1 extra-large.