Finding down payment money

[Sara Frank]

Hi everyone! I'm based in DC and found the perfect house hack deal - I have a preapproval letter but I don't have the full amount for down payment and closing costs. My parents aren't real estate savvy and not open to lending the money - I was wondering where people find this kind of capital? (its only $15,000) (sans taking a second loan which is not viable for me) 

Thanks! 

PS This would be my first deal!