adding Bonus Items or Free items given by Suppliers #
2 ways you can do this:
Solution 1: #
When adding purchases simply make the purchase price 0 for the free items.
Solution 2: #
Find the average price of the item and use that for the unit price.
for example, if you purchase 10 quantities for a price of $2 each, 10X2 = $20
and get 2 quantities free, then the average cost of each will become 20/12 = $1.66