use Math::Round qw(nearest);

  $quote = 418.00;
  $price = nearest(10, $quote);
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I don't know if it's important, but this implementation deals properly with negative numbers. From Math::Round:

sub nearest {
 my ($targ, @inputs) = @_;
 my @res = ();
 my $x;

 $targ = abs($targ) if $targ < 0;
 foreach $x (@inputs) {
   if ($x >= 0) {
      push @res, $targ * int(($x + $half * $targ) / $targ);
   } else {
      push @res, $targ * POSIX::ceil(($x - $half * $targ) / $targ);
   }
 }
 return (wantarray) ? @res : $res[0];
}
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Cheers,
Matt