Are you planning on selling wholesale then? You would obviously have to determine a reasonable price that you can make on each item that is worth it, both to you, and to the retailer once they place the appropriate markup on it. As far as the bulk buying, you would want to give the retailer an incentive to order more product, through lower cost structures, that is the nature of the beast.
I really don't know for sure how you would best set up the structure, and I hope someone else here will pitch in because this is an area of weakness for me as well, But I will issue this forewarning: For a young startup, the chance of most retailers ordering exorbinant amounts of stock is slim, especially when they have not yet seen the power your line has. They will have to try it out first, and see what happens.
But keep at it, and stay positive, and it will go your way in time.
(4.) What do you mean by tricks, by the way??
bulk buying - selling to retail stores - how do I setup pricing? 
