Here: https://pokemonrevolution.net/forum/viewtopic.php?f=120&t=29668
TM114: Rock Smash - FREE Route 11 Stop House 1F after obtaining 30 caught Pokemon / Celadon Mart - $3,500 / Route 36 Smuggler - $5,000 / Mauville City House 2 - $5,000
For the story I don't remember you need rock smash in seafloor anyway.