Details as follows:-
1. Retails price 1 for order qty 1-2 pcs.
2. price rate 2 for order qty 3-11 pcs.
3. price rate 3 for order qty >=12 (but for the same retail price 1 only )
May u please quote me the price and lead time.
Thank you,
Chat Conversation End
Could u have a look at this plugin?
I think this is similar stuff u need, except the same category restriction.
I can adapt it for you if u want.
Have a try at the site which is already using this plugin as well. So u'll know what really it is.
http://virtuemartoz.com/other-virtuemart-extensions/category-discount-for-virtuemart.html
Or see the "official" plugin: http://extensions.virtuemart.net/products/quantity-related-price-calculation-detail