There are various ways to add discount to the cart:
Try these:
20% off on Cart Value of USD 500 and above: Use Code- PROMO1 Flat $5 discount on purchase of $30 - No coupon required
30% off on Cart Value of USD 600 and above: Use Code- PROMO2 Flat $8 discount on purchase of $40 - No coupon required
Buy 1 Get 1 FREE:This can be used to offer discounts like buy one get one free (100% discount) when any combination of products are purchased. Example: go here and buy the first 3 products and you will get a product FREE (the one that is cheapest of all the 3 you purchased)
Other Discounts that are possible and the user manual comes with detailed explanation of how to do that:
Order total discount percent Order total discount amount Order quantity discount percent Order quantity discount amount Set order total discount percent limit Can be set to ignore certain products for cart wide discounts Item quantity discount percent Item quantity discount amount Multi quantity discount percent Multi quantity discount amount Multi total discount percent Multi total discount amount combi quantity discount percent 1+1 type offers + many more...