I don't think you understand the term "margin". Margin refers to a loan against marginable securities. That's where the brokerage house borrows money on your behalf and settles the trade (the seller gets full payment no matter what).
If you bought more stock than you have money in the account for, that's OK. You don't get ownership when the order is filled; you have three additional business days to settle the order. That means that you have three days to top up your account with cash and if the seller has paper certificates, he has three days to deliver them to his broker.
If you buy more than you have cash for and sell out in a few days, the broker ends up covering you, because the purchase was settled for payment in full three days after purchase and your sale was settled three days after the trade that sold it (it doesn't cancel the original purchase). If the securities aren't marginable, or you are in excess of margin, the broker can't loan you margin money which means that he can't collect interest; he's covering it with the brokerage house's own money for free. This gives you a free ride.
Different brokers have different ways of handling this. Some don't let it occur in the first place by simply refusing to accept an order in excess of what's in the account at the time the order is placed. Others will accept that errors happen and ignore it once in a while, especially if it's a particularly good customer. At some point the broker can say this is happening too often. You must be free-riding on purpose, and close your account. Remember: the broker is being monitored for compliance and if this happens too often, they will be fined for not enforcing margin rules.
It depends on what your account balance was before the purchase and after and what other securities are in your account.
Stocks selling less than $5 a share are not marginable (they do not have loan value), therefore the amount due of the purchase will be 100% of the cost of the trade.
Yes you can buy stocks less than $5 a share, but the brokerage firm will not lend you any money., thus the total amount is due
The firm will compute how much buying power you have, using the market value of the total amount of securities in the account (but will not count securities selling for less than $5) and will multiply the total market value by 50% and then subtract any debit balance.
If this produces a positive number, your account will be in compliance, if not, the firm will ask you for money.
At the worse, the firm will request additional monies. If you fail to come up with the money, the trade will be liquidated, and you will be obliged to pay any debit. Then your account will be restricted for 90 days, so that the next time you purchase, the money will have to be in the account before the trade is accepted,
Every brokerage is different. I know my margin won't let us use margin for anything under 5. You will probably have within three days to liquidate or add more funds to your account. Good luck, i hope you can trade that stock for a small gain and get out of your predicament.
You didn't buy it on margin. Your account paid the full price for the cheap stock and used margin from some other shares in your account that are marginable.