Seeing you are already familiar with VLookUp, why not just use that. Put a
simple VLookUp against each item  in your new list, to look itself up in the
old list. If it's not there, you'll get a #N/A. If you get the new VLookUp
to return the price, you'll also be able to compare  the new and old prices.

(You can of course create just one VLookUp, then copy it down for all the
items in the new list.)

The only thing this won't find  is items  that have been removed from the new
list.

But, why do you have to add  individual new items to the old list? Why not
just replace the old list  entirely with the new list?