If your currency is well programmed and has a future, all platforms will scramble to list it without taking any fees from you, but you need the currency to be well programmed and solve a real problem in an innovative way.
Other than that, you need to pay a lot of money in marketing first and then for the listing fees, if you do not have enough cash, you will not be able to keep the price of your currency high (continuous and increasing demand) and thus it will die over time.
Yes, you're spot on there. Listing prices do depend upon their belief in the project and the cooperation between the two parties. They will usually also offer paid marketing services to their own community which is also price-variable dependant on the project.