This app was mentioned in 17 comments, with an average of 3.06 upvotes
I've been using Grana, which was developed by a redditor. Simple interface, so if you want to micro categories and stuff like that you will need something else.
https://play.google.com/store/apps/details?id=com.renanferrari.grana
https://www.reddit.com/r/Android/comments/2su1yh/my_first_app_is_a_super_simple_and_practical/
I think I prefer Grana - Expense Manager to this one, since it seems to offer the same (if not more) features but with a much more likeable design.
A couple of apps I've enjoyed recently:
This very simple little app is a very easy way of tracking your spending habits. It doesn't link your bank account, you just enter your incomes and expenses, but as a student needing to keep an eye on how much I spend on things it's perfect. Also, one of the most attractive apps I've ever seen.
I've cycled through a few SMS apps recently, and of all of them this is the one that has impressed me most. It is by far the most customisable and adjustable messaging app I've come across. From themes to choosing which buttons to display on pop up notifications, to changing notification settings for unknown senders or non-numeric messages.
My personal favourite icon pack. Just pretty.
I've never had so much fun from an app that's not a game. Leon is a theremin emulator, which is great for trying to play the Doctor Who theme or making it sound like aliens have landed. It's better than it sounds, honest.
Edited for formatting.
I use Grana. It's not "textbook" material design but it's very nice:
https://play.google.com/store/apps/details?id=com.renanferrari.grana&hl=en
Grana is super simple and easy to use.
Grana might be something that you are looking for.