@renevanbelzen I hear you; being on a budget can be an exciting challenge indeed. 😅 But it's doable! We live in the era of dirt-cheap computing, after all.
Raspberry Pi 400 has more than enough computing power for web development and comes with a keyboard, mouse, power supply, and SD card. It will set you back like €109 and should last at least a couple of years. My first Raspberry Pi turns 9 this year and still boots up just fine. Your mileage may vary. 😉 Of course, you will need a monitor or TV to plug the computer into, as well.
And if you want to spend no money at all, there may still be alternatives out there. For web development, all you really need to get by is access to a web browser. Here in Sweden, you can walk into most libraries and use computers with internet access for free. There are also hackerspaces, cafes, and other communities that offer free or cheap access to computing power. Maybe you have similar options in the Netherlands?