if($seller == $login) {
$errormsg= "".Cant_buy_from_yourself."";
}

if($seller == $login) {
echo "".Cant_buy_from_yourself."";
return 0;
}

<td width="50%" align="center"><a href="?op=market">...(дальше не трогать)
<td width="50%" align="center"><a href="?op=market&viewcat=special">...(дальше не трогать)

<td width="50%" align="center"><a href="?op=market&viewcat=21">...(дальше не трогать)
<td width="50%" align="center"><a href="?op=market&viewcat=20">...(дальше не трогать)

  if($_GET['id']) {
       $get_item_id=$_GET['id'];
       $cat_id_s="and cat_id = '$cat_id' and item_id = '$get_item_id'";
      }
     }

$get_market_items_ = mssql_query($get_market_items);

      //GodLan Sort Table      
      if($cat_id == $cat_id) {{
      $get_market_items="SELECT TOP 1000 * FROM [maw_market] where cat_id='$cat_id' and is_spec_offer<='0'";     
      }
      if($cat_id == '21') {
      $get_market_items="SELECT TOP 1000 * FROM [maw_market] where is_spec_offer<='0'";
      }
      if($cat_id == '20') {
      $get_market_items="SELECT TOP 1000 * FROM [maw_market] where is_spec_offer='1'";
      }}
      else { $get_market_items="SELECT TOP 1000 * FROM [maw_market]"; }
      //End of Sort Table

print "<div class=\"msg-ok\"><ul><li>".You_have_buyed_the_item." (".Item_price.": $price $pay_type)</li></ul></div>";

writelog("buy","<b>$login</b> Has Been <font color=#FF0000>Buy</font> Item <b>$serial</b> Price: $price $pay_type from $seller_acc");