@price = ('12p', '18p');
@{$tbls{'12p'}} =  [ 't72', 't73', 't74', 't75', 't76', 't77' ];
@{$bases_tbls{'18p'}} =  [ 't73', 't74', 't75', 't76', 't77' ];
for $b (0 .. $#price) {
	$sql = 'SELECT respondent FROM';
	for $i (0 .. $#{$tbls{$price[$a]}}) {
		$sql = $sql.' ${$tbls{$price[$a]}}[$i];';
		$sta = $dbh -> prepare($sql);
		$sta -> execute() or die("Could not execute!" . $sta->errstr());
		... a bunch of stuff ...
	}
}