A: If you don't want to pay, then you can either use photos you own the copyright to, use photos that are in the public domain, or ask nice and maybe they'll give you permission. (people always seem to forget that last option)
A: Star registries are a money making plot. You don't actually get anything as nobody has the "right" to name a star and there's no official star naming body.
I could name Jupiter "Walter" but doing so would be meaningless as there is no statutory system or basis for naming the planets. It is just tradition.
So as Mr Overhauser said, they may print a book and your name in the book would be part of their copyright, but the star remains whatever people call it by tradition.