Learn English – ‘I wish’ and counterfactual

You would get the same answer to each question whether you used would or does; both questions ask for the price of the action mentioned. There is a slight difference in the implication of why you're asking, but the information you want is the same.

When you ask How much does it cost to [x], you're simply asking for information. You could be asking out of pure curiosity, or because you want to purchase the item in question, but no implication is made either way.

When you ask How much would it cost to [x], there is a stronger implication that you're wanting to buy the item you're discussing. Instead of a straight pricing inquiry, you're saying "If I were to buy [x], how much would it cost me?" Using would introduces a future conditional, thus the implication that you're considering the purchase (based on the answer to the question about price).

Wouldn't is a contraction of "would not" and denotes a lack of permission or willingness on the part of the subject. Your father didn't want to let you borrow the car, and the landlady didn't want you to have guests.