Credit score

How am I supposed to build credit when I can't get approval for one single credit card my whole life. I'm 25 everytime I've applied for a loan Or card I was denied because I have no credit and they affected my score  just for applying to build credit it's a screwed up system that I have never been able to figure out. Turbo tax says my score is 524 I want to get a small loan and pay it back quickly does anybody have advice on how to get a small cash loan?