It depends if it is judged to be deceptive conduct, so it is relevant how the information is presented. Burying conditions in the terms of service or contract, but then misleading people with other information on a web page, can mean that the preferential interpretation stands. Standard verbiage in the contract like 'this contract is the only terms of the contract' is just meaningless (except for specific categories like auctions and real estate, where other provisions may still apply, like the cool off period).
One example of the consumer law being applied is in regard to drip pricing, which was commonly used by airlines and hotels:
https://www.accc.gov.au/consumers/online-shopping/drip-prici...
https://www.accc.gov.au/media-release/airbnb-and-edreams-giv...
Pricing rules, in this case Partial Pricing, are quite clear:
If you promote a price that is only part of the total price, the total price must also be displayed at least as prominently as the partial price. This means customers should be able to identify the total price in the advertisement at least as easily as prices for any component parts.
https://www.accc.gov.au/business/pricing-surcharging/display...Also relevant: subscription traps:
https://www.accc.gov.au/media-release/accc-warns-consumers-t...
I am unfamiliar with consumer protection in DE, and publicly owned services like the railways may have special pricing legislation, but new EU harmonized laws are being introduced for digital services:
https://www.linklaters.com/en/insights/blogs/productliabilit...
Sadly, the EU system prevents any member state from having stronger protections.
For subscriptions there are already strong rules about clearly indicating the total price, and the amount that is fair for early termination:
https://www.osborneclarke.com/insights/distributing-games-in...