Raspberry Pi’s are no longer the cheap $35 single-board computers that they once were. There are however quite a few alternatives, but all lack or add some features. Of course, the Pi has also improved quite a bit.
But even with the Raspberry Pi itself, it is worth buying for what you need to get done. Sometimes something smaller does the job just as well. A Raspberry Pi can be a complete overkill for many tasks.
For benchmarking purposes, the Pi Zero 2 W costs $15 and the Pi 4 Model B with 2 GB of RAM is $45, and the newest Pi 5 with 4GB of RAM is $60. Then usually a case and power supply are also needed with it (another $24).
See https://www.xda-developers.com/best-raspberry-pi-alternatives/