With a starting capital of $15,000 surely you can make $5,000 profit through day trading in a month and you can earn more than that depending on your capacity and skills you have in trading. The amount you can earn depends duly on your own self because if you are bad at it, then the possibility could turn things the other way around. So be mindful before engaging on such, you must be knowledgeable enough on managing your assets and funds to somehow assure your earnings by the end of the month.