Hi,
Just tell them what the cost is and reference the website. If they are in business, they must know they have to spend some money. They are not students eating ramen noodles.
Sure. Just be up front ... tell them that you want to create a DO account to produce the work, so they can keep their server information private for now. At one point, the code you write will have to be uploaded to their account. That said, once you get to that point, you should have established some trust.
Stef