@Shred Dude this 
=SUMPRODUCT(Sheet1!B1:B10)*(-ISERR(SEARCH("MON*",Sheet1!A1:A10))+1)
just sums everything.

@xld, this seems to only work if the only thing in A1 is "Mon" if there is anything else it returns 0, the other problem is if "Mon" appears anywhere other than first it's also summing that one.

Any ideas?