Sure. Completely free. You only need to click in "Download now". There are executable files to play directly (Windows or Linux) and a .tap file to play in a ZX Spectrum emulator (128K models).
Does it work on Chromebook?
The thing is, I dont have PayPal or a credit card. I also don't want to accidentally pay for something without knowing it.
In Chromebook you need to install a free ZX Spectrum emulador like Speccy and use the .tap file