Adopt one day

So I want adopt a dog in couple weeks but first I wanna find a job so my family won't give me a shit about not taking care of my dog. And I'm very serious about adopting a dog and love him as my own child, btw I'm 20yo.

So I wanted to ask, is it hard to take care of the dog financially? Like food, toys, healthy dog stuff... I'm only scared for medical bills, that one day I will need to go with my dog to see vet and later will have to buy expensive medicine or other stuff like that.