function rand_float($st_num=0,$end_num=1,$mul=1000000)
{
if ($st_num>$end_num) return false;
return mt_rand($st_num*$mul,$end_num*$mul)/$mul;
}

$num= rand(1,3);
include_once('db_connect.php');
for ($i = 0; $i < $num; $i++) {
$req = $mysqli->query("SELECT * FROM `coinInfo` WHERE coinName = 'BTC'");
while($row = $req->fetch_assoc()) {
$ask = $row["ask"]/100000000;
$bid = $row["bid"]/100000000;
}
$operation = array("BUY", "SELL");
$rand_keys = array_rand($operation);

//

$int = mt_rand(1,4)/10000;
$fractional = mt_rand(1,99) / 10000;
$float = $int + $fractional;

$price          = rand_float($bid,$ask);
$amount         = $float;
$type_operation =  $operation[$rand_keys];

$Responce=create_orders($mysqli,$sesion_id = 299,$contest_id = 1,$price,$amount,$name_val = 'USD',$name_prod = 'BTC',$type_operation);  
}