my %colnum_for_name;
$Worksheet = $excel->Worksheet("...");
foreach my $col ($Worksheet->{MinCol} ..  $Worksheet->{MaxCol}) {
   my $cell = $Worksheet->{Cells}[0][$col];
   if ($cell) {
       $colnum_for_name{ $cell->{Val} } = $col;
   }
}

# later
my $someval = $Worksheet->{Cells}[$x][$colnum_for_name{'price'}];