The studios typically pay for it and it's usually arranged prior to a big film opening for promotion. Foster had been offered that opportunity several times before, but she always turned it down because she says she wanted it to coincide with a project she was directing, and Money Monster is the biggest studio film she's directed, so that's probably why it all came together now.
"Oh I went there, bought a house, moved in b*tch, and now I'm remodeling the kitchen."

I think you have to pay for the star, so she was probably waiting for a studio to front the money as part of a promotion. Some celebrities probably pay for it themselves. Kim Kardashian wanted to buy one, but the walk of fame does has some standards - allowing her a spot if she wins an acting award as a reality star.

How in the world did Jodie Foster not have a star until now?!

Congrats to Jodie! Well deserved.
Do you need a bowman!?

I agree i think she should have gotten this along time ago she is a powerful actress

I didn't know that.I guess that explain why some of the lesser stars are on it.

The Hollywood Walk of Fame ceremony is less to do with an honor now than a tie-in to a movie opening. This is probably to get some publicity for Money Monster. The star (or the studio in this case) pays for the walk of fame.

About time
She deserves it more than some of the other guys on there already