What would be a better choice a cat or a dog?

Both of them would be girls and both of them would end up getting spayed, I wanted both but I can't afford both and give them as much as attention as both of the need so I can't decide which one I want The cat would be a female Birman and the dog would be female and it would be a Papillon, I am a huge couch potato and I go to a full time college I don't live on campus but I live In an apartment with my best friends and as soon as I get home id mostly be hanging out with her and whichever pet I choose or you help me choose but I can't decide I need to have whichever one would cost less for vaccinations and everything anything you can help me with would be great.