The other day I posted a code to unlock 5,000 free coins, but there was an issue and it did not work. However, I now know why! It turns out the code TUBERUN as said on the board is incorrect. Somehow it was misprinted. The correct code for 5,000 free coins is actually TUBERIDE. I just tested that code and I can confirm TUBERIDE actually works!
Enjoy the 5,000 free coins, and special thanks to @Dcamp_ for telling me about the correct code.