This help page explains our discount feature and settings in detail:
http://www.e-junkie.com/ej/help.discounts.htm
You can set up a product-specific discount that marks down the per-unit price of the item when the buyer orders a min. quantity of 2 or more of that product. Note that this adjusts the price by a flat amount rather than a percentage, and 30% off the second unit would be equivalent to 15% off each unit, so you'd want to figure what 15% of your product's per-unit price is and set the discount to that -- e.g., if your original price is $50.00, then 15% of that would be $7.50, so you'd set the discount to markdown the item price by 7.50.
