ช่วยด้วยค่ะ !! [PHP] เปรียบเทียบค่าที่ีรับมากับฐานข้อมูล

$text1 = $_POST['text1'];
$text2 = $_POST['text2'];
$text3 = $_POST['text3'];
$month = ($text2*12);
$money = $month*$text1;
$pay = $text3+$money;



echo "If you have $pay Baht, You will buy these car ";

$prize = "SELECT prize FROM car WHERE $pay<=$prize";
$sql="SELECT * FROM car WHERE '$prize' <= $pay ";
$result=mysql_query($sql);
echo "<table border='1'>
  <tr>
  <th>Model</th>
  <th>brand</th>
  </tr>";
if($row=mysql_fetch_assoc($result)){
	echo "<tr>";
    echo "<td>".$row['Model']."</td>";
	 echo "</tr>";
  
	
}
 echo "</table>";