That won't do anything. That would just be supporting a pirate. No proceeds would go to the ACTUAL developer of this game, mystman12.
Viewing post in Baldi's Basics plus mod menu comments
I argue that making this listing cost money is WORSE than making it free, as that would mean money would be going to a pirate. Buy the game from mystman and install oldsport's mod menu yourself. And yes, I believe this lister stole the mod menu from oldsport - the screenshots literally say "oldsport's mod menu".
And just in case you didn't know - Baldi's Basics Plus is NOT owned by peyton36. It is owned by mystman12, better known as the company Basically, Games! who did not give the lister permission to reproduce and redistribute the game for free.