If you want to delight your potential customers, ask for it after the free trial. It's a way to garner instant respect and trust. They're most likely used to

If you want to delight your potential customers, ask for it after the free trial. It's a way to garner instant respect and trust. They're most likely used to being asked for their credit card up front and having bad experiences (or scared of having a bad experience). I'd definitely be more willing to try and eventually spend money on a product where the company understands the spirit of a "free trial".