How did you potty train your son?

My son is two and turned two August 4th. For the past month he has started ripping his pull ups off, they’re so expensive I don’t have the money for him to be doing this all the time and he does it about four times a day. Taping it won’t work because he still finds a way to rip it off. A few minutes ago he pulled the diaper down far enough to pull his penis out and peed in the floor. On purpose. He absolutely will not go on the toilet at all!!!! I’ve tried potty training three different times and every time was an epic fail. I even tell him if he goes he gets to wear big boy undies instead of little baby diapers. I’ve tried the underwear before and he loved them but I can’t let him wear them if he’s just going to keep peeing all in them instead of going to the toilet. I need help. Before anybody says anything about letting him go with Dad to the bathroom his father isn’t around so that’s not an option.