I live in Budapest and regularly have to go to Wien. If you buy the ticket from the hungarian railways it costs the half or less than compared to the austrian railways.
It's too bad that the Czech train hack doesn't seem to work any more: There's a train from Berlin to Prague that stops in Dresden. It used to be much cheaper to book the trip Berlin-Dresden with České dráhy, compared to the price you get with DB.
I think you also had to make it an international ticket to make it work, booking the journey from Berlin to the first station after the border. And then just leaving the train early, at your intended destination.
I really appreciate seat61.com when I need to book train travel. The site is full of info as to when and where to book to get the best price, as well as what level of service various trains in various countries provide.
I live in Budapest and regularly have to go to Wien. If you buy the ticket from the hungarian railways it costs the half or less than compared to the austrian railways.
Example: next monday
Hungarian BP>Wien https://i.imgur.com/9rZgB8c.png
Austrian BP>Wien https://i.imgur.com/mn95IrV.png
Hungarian Wien>BP https://i.imgur.com/GymMOaW.png
Austrian Wien>BP https://i.imgur.com/zN3VCDv.png
I always tell my friends coming from Germany or Austria to buy tickets from the hungarian railways because it's much cheaper.