Macro to update prices if new one exists

[tonywatsonhelp]

Hi Everyone,
I have a list of products and there prices, I'd like to update them
the problem is not every item is in the price list so i need a macro to remember what was there before and only replace it if it finds a new price.

So if I was writing this in English it would go like this,

For each cell in range P25:P and last row "M"
Old Price = cell value,
product = Cell offset -2 columns value

look in sheet "Stock List" Column I and find "product"
if found the new price = same row column K,
if not new price = Old price

cell.value = new price

please help if you can, I know i'm almost there but missing something.
Thanks
Tony