I currently have a look up table and use the following formula:

=VLOOKUP(C2&D2&E2,All_prices!$A$2:$H$33,8,FALSE)

However, if any of the attributes in columns C D and E do not match, then
#N/A is returned (in this case Cell G2). This is causing a problem when I try
to total colum G. Is there a way of returning 0 instead of #N/A? I hope this
makes sense...