Not an app, but a podcast & books.
She’s on the money – by Victoria Devine.
She has changed my life!

I agree with the comment below about The Barefoot Investor. It is a book well worth reading.

It might depend what you’re looking to achieve.There are a few apps out there but a real lack of good ones, IMOH For me, I have written down a budget since I moved out of home when I was 20 and I still maintain this habit. If I don’t follow it and have it written, I 100% spend it EVERY TIME! In the last 5 years I read barefoot investor and follow those principals. I got rid of all debt and made sure I had the best deal I can get for bills. I have a weekly budget written in a note book just for that purpose and when I need to adjust ongoing I write it out again. Every pay I refer to my budget, pay my bills ahead of time and every fortnight rather than at the time I get the bill (electricity $350 in credit, phones 3 months in credit, internet 2 months in credit). I use all apps related to my bills where possible so I can ensure I’m ahead and of what I’m paying. I also make sure I save a little and put $20pf into an online share account, which I don’t miss but suddenly have $4000 worth of shares!! I find it’s not the big bold things I do but these minor habits on a continual basis. If I find an app that will help this habit and support my intentions, I’d grab it both hands but so far I’ve not found anything worth changing my current set up for. They’re over complicated!

I’ll be checking back here to see if anything helpful is suggested