This got really complex, I can understand your confusion. Does this work for you? I've tested it as thoroughly as I can think to in a few minutes:

#!perl 

use strict;

my @data = qw/ +20 400.00 $5,000.00 -$860.7 $-26.01 90,000,000 blah te
+st 45$99.0 $5+8.2 $,000 /;

for (@data) {
    if (/^(\$|-|\+|\$-|\$\+|-\$|\+\$|\d)/) {
        if (/^\d((,\d{3})|(\d*)|(\.\d{1,2}))+$/) {
            print "$_ is a numeric!\n";
        } elsif (/^(\$|-|\+|\$-|\$\+|-\$|\+\$)\d{1,3}((,\d{3})|(\d*)|(
+\.\d{1,2}))+$/) {
            print "$_ is a dollar amount!\n";
        } else {
            print "$_ is non-numeric!\n";
        }
    }
}
[download]