How could I replace the cover page of an existing book with my custom one?

As a Christmas gift I’m thinking of getting an existing paperback book but putting a custom cover on it. I’ve had a look online and can’t see any services where they let you order a book with a custom cover of my design. I’ve also found some videos on how to do it myself but I don’t have the tools needed like the specific paper or varnish and it would be a shame to have to purchase it all to only change one book cover.

​

Has anyone here attempted similar before? I’m hoping that I’m just Googling the wrong terms and this might actually be something I can find either online or in a shop (I’m in the UK but let me know of any services you know regardless as it might put me on the right track here). Thanks

by TheAngriestLlama