There are indeed some very legitimate reasons for a modeling agency to ask you for money – AFTER they have proven themselves to you. (Clients pay models. Modeling agencies don’t pay models – models pay modeling agencies for getting them work.)
Can I wear jeans to an audition?
You don’t need to dress like you’re going in for a corporate interview here. Your clothes shouldn’t be a wrinkled mess, but you also shouldn’t be wearing business attire to an audition. A good pair of jeans can go a long way, and it’s worth investing in a pair for auditions alone.