With capital of $7k, I think it will be quite easy to make $30 in one day, as long as you are good at managing your existing finances. Just buy BTC and please manage your assets to get profits of up to $30 per day
How will he get upto $30 per day on just bitcoin investment without doing anything, he may engage in making trades and that is if he has the sound knowledge of doing trading, he can also Invest and hodl for long but this is not what you will just have tour asset in bitcoin just to be expecting thirty USD every day as a return on investment, many organizations may give such promise if you invest with them but doing that is at your own risk.