Something like this perhaps? 
#!/usr/bin/perl

use strict;
use Data::Dumper;

my %sum;
while (<DATA>) {
    next if ( /^ID/ || /^\s$/ );
    my ($id, $value) = split( "," );
    $sum{$id} = $sum{$id} + $value;
}

print Dumper \%sum;

__DATA__
ID,Value
FB208025,1629.01
FB208025,1201.16


FB091027,1257.66
FB091027,741.92

FB135022,11210.66
FB135022,3238.67
FB135022,3569.34
FB135022,5534.23

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In reply to Re: Getting combined values via a hash by bichonfrise74
in thread Getting combined values via a hash by mmittiga17

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