i am trying to rescuse the drill guy and it just told me that i need to…

i am trying to rescuse the drill guy and it just told me that i need to buy a stick of dynamite to blow up the rocks so that the bandits will open the gate and i can sneak through but i didnt unlock the dynamite thing in the store and now i cant because i dont have enough experience points what do i do?!?!?!?! somebody help please