The Purchase price didn't updated automatically

I started using Manager and its so good, there’s some thing that I couldn’t see:
1- The new Items Purchase prices should updated when I create a new Purchase invoice with new price, at lest I should have see it in reports or in Inventory Items form as a single column.
is there such thing or should I updated it manually every time?
P.S: I’m talking about actual price not average cost.

only the purchase price entered for the inventory item under the Inventory Items tab will show automatically on your purchase invoices. actual prices at which an inventory item was bought previously will not appear on new purchase invoices.
please read the guide

The purchase price you define for an inventory item is only a shortcut for filling in transactions like purchase invoices or purchase orders. It is completely optional. In fact, if the price at which you buy something fluctuates frequently, it would probably be best not to enter it at all. Having a price already filled in that does not match the supplier’s price might mislead users to believe they do not have to adjust the unit price.