Just log into url content via file_get_contents. Your page actually returns a JSON string to get these values into meaningful data, decode them through json_decode, and then access the relevant data:
$url = 'http://pubapi.cryptsy.com/api.php?method=singleorderdata&marketid=132';
$data = json_decode(file_get_contents($url), true);
$sellorderprice = $data['return']['DOGE']['sellorders'][0]['price'];
echo $sellorderprice;
0, . , , , foreach:
foreach($data['return']['DOGE']['sellorders'] as $sellorders) {
echo $sellorders['price'], '<br/>';
}