Need help!!

I do have a friend that has $40,000 to buy a house cash,and i found a couple houses here in NJ from $20,000 to $30,000,but i don't want him to know that of course because i want to put the $10,000 in my pocket....
My question is how can i make a deal to the Bank without him know the right price???
Because I'm not a Real Estate Agent,also i don't have the $20,000 to buy myself and sell for $30,000?
Is possible to close a contract with the Bank or a Realtor without any money down?
Please i need help to close my first deal with u guys that are already in this business for long time.
If anyone lives in NJ like me it'll be very helpfull..

Thank you

Andre