YNAB (and surely other apps) works that way. Your money is affected to the budget you want, not "free to spend". They have a nice 9 day course about managing your budget (Email: https://www.youneedabudget.com/method/nine-day-course, PDF: http://www.youneedabudget.com/downloads/9DayCourse.pdf)

I may be a bit biased because I really love this app, but it helped me a lot to stop throwing money on useless things.

Side note: Jesse (founder of YNAB) is an amazing speaker with a great sense of humor. His story about bootstrapping YNAB is hugely inspiring to me. I highly recommend his 2014 Microconf talk (https://vimeo.com/95653848) if anyone is interested.