Du kan sende en række formularelementer, bare skift din markering til:
<input type="checkbox" name="prices[]" value="Less than 10,000, ">
<input type="checkbox" name="prices[]" value="10,001 to 15000, ">
// etc...
Derefter PHP-siden:
$prices = $_POST['prices']; // this is now an array, work on it