I want to get a pet hamster?

I haven't had a pet in 10 years. ( i had a dog when i grew up with until i was 7). The thing is i want to be responsible for things in my life, so i can learn responsibility. since i can't get any affection from my family, i want to get a hamster, and probably move up all the way to dogs/cats(when i live alone) If i get a hamster, will it be expensive? Will it need vaccine shots and how many visits at the doctor per a year? I want a hamster that won't run away, any suggestions? I'm 19. Pros and cons if you can? Thank you in advance.