Wills that have been admitted to probate are publicy available from the Probate Office for a fee that is much less than €78.
What these people are doing, for the fee they charge, is searching to find if a will has been admitted to probate for the person you name and, if it has, getting a copy of the will and sending it to you.
It's not illegal but you could cut out the middleman and deal directly with the Probate Office yourself for a fraction of the cost.
I'm aware its much cheaper to go direct to the Probate Office. I actually don't need it as i have all the originals. Its just that it was a bit of a jolt to see my mothers name, address and mine on a commercial website without my consent used to sell a service run by a "Irish citizen in London" .