Not sure what the sales are like on PS but at least on Steam you can find great deals for the digital copies as well. (You lose the reselling though)
I'm in the UK, and CeX is a great shop to trade in a game for store credit once I'm finished with it, then pickup whatever I want to play next. Most of the time I can completely cover the cost of the next game with the credit received from the trade, or use some store credit leftover from a previous visit!
For PS4 you can buy the disc version for €19.99 regular price and €17.99 on sale. Used discs start from €9.
If you don’t mind waiting for a sale then Steam is great. Otherwise PlayStation is a better deal.
Steam is the entire reason I even bought an offline PS4Pro in the first place!. Years ago, they required an update from Win7 to Win10 (in order to keep playing my therapeutic GTA5, which for some reason required an online connection for single player gameplay?!?!). After some rageful months without Trevor'ing, I bought my first-ever gaming console – love it. Stays offline, just in case Sony wants to brick my PS4, too (fucking hypothetical corporate bullies!)...
Imagine a day where Sony drives around with trucks broadcasting WiFi signals instructing rogue, ostensibly-"offline" PS5s to self-destruct, via backdoor GHz...
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Welcome to /hn/ – I've appreciated many of your varied contributions (keep it up!).