No disrespect meant to PawelDecowski at all (his CC number validator looks awesome, I'd use it) but he couldn't monetize it even if they he wished to -- too much competition in that space. Nobody is going to even pay $1 when they can just go on GitHub and find several similar libraries which do somewhat similar things.
I think £55 a year is best case scenario. At least it likely covers web-hosting costs.
I think £55 a year is best case scenario. At least it likely covers web-hosting costs.