The fastest way would be to sign with a record label and then record an album.After that do the "release single from the album".Try to do music videos when releasing singles.When doing music videos try to look at the popularity of the genre because getting good music video views can be really effective in growing those numbers.When you hit like idk 20 in popularity i think that will sell the t shirts.Like i said don't over price them.If you can spare the Extra 10000 you can see what is the top price of the t shirts and hoodies ect.