If you're looking to pick up a classic disc-based retro gaming system these days, then it's worth investigating the world of Optical Disc Emulators—ODEs, for short—as these devices allow you to load game files without having to purchase expensive copies on the secondary market.
One of the most popular ODE options for PS1 is xStation, but it seems as if a new low-cost alternative is now available.
As highlighted by modder @TZMWXdiyer, the PicoStation project allows you to create a cheap PS1 ODE using a Pico 2040 and an SD card slot.
"A few days ago, I discovered that Johnbaumann updated the PICOSTATION project of Paulocode on 2024/12/10," says the modder. "I modified two motherboards: one with the PICO module directly soldered onto the board, the other connected to the Xstation slot via an FPC cable. Both machines run great, with significantly improved compatibility. Now, you only need one PICO 2040 and an SD card slot to achieve a cheap PlayStation ODE."
While this is indeed a cheap ODE option, it does require some soldering and modding skills, so it certainly isn't as easy as, say, the Saturn SAROO flash cartridge or even the plug-and-play PSIO—although the latter option has some serious issues.