Just grab all the prices into an array, then use the ones you want:

use warnings;
use strict;
use Data::Dumper;

while (<DATA>) {
    my $line = $_;
    my @prices = $line =~ m[(\$\d?,?\d\d\d\.\d\d\b)]g;
    print Dumper(\@prices);
}

__DATA__
"18-December-09";"$1,104.50 ";"29-July-97";"$326.55 ";"25-April-85";"$
+322.50 "
[download]

Prints:

$VAR1 = [
          '$1,104.50',
          '$326.55',
          '$322.50'
        ];
[download]

See Global matching