How to see last sale price and purchase price of a particular item for a particular Ledger?
You can just press F12(Last Purchase Rate), F11(last Sale Rate) and F10(Last Purchase Rate for ant Ledger) in Rate box of Sale and Purchase transaction frame.
Go to Transaction > Sale/Purchase (Open any one as per your requirement)
Then select a Ledger.
Select an Item which you want to sale or purchase.
Then press F12 = It shows last purchase rate, F11 = It shows last sale rate and F10 = It shows last purcahse rate for any ledger in Rate box.