Bottle cleaner!

blue

I am currently off work so I don’t have a lot of extra cash to be buying stuff I don’t need but I recently learned from my SIL that she has a bottle sanitizer or cleaner. She said you HAVE you have it for the bottles, now I’m curious because they can be pricey lol I know I would have to do a weekly boil to deep clean them but after every use?

My question is- do you use a sanitizer for the bottles? If so, do you find it to be a necessity?