I paid a $100 adoption fee for my puppy. She needed several visits to the vet afterwards, at around $120-150 each. Spay and microchipping was $150.
Ex-pen to keep her in while we are at work - $60
2 dog beds - $40
Stainless steel bowls - $12 off of
ebay
Potty pads - ~$20/month, though we are teaching her to go outside
Treats and chewies - I spend $10-15/month on these
Toys - ~$5/month, though she is learning to destroy them
Food - not much, she's a lap dog. I paid $25 for a big bag of Kirkland food, and she's still not through it. Will be switching to a more expensive brand.
Collars and leashes - 2 collars @ $6 each, 2 leashes @ $6-7 each. She likes to chew up her leashes.
Crate - free, from my old cat - he was shipped to me in it
She's definitely more expensive than my cat. I adopted my cat for $75, and he was neutered and microchipped when I got him. It's $100/year for his check-up, but $60-100 to take him in when he gets sick.
When it comes to pets, expect the unexpected. My "old" cat passed away at 2 from a terminal illness. I spent about $3k on the last six months of his life for palliative care. My puppy costs us unforseen costs in things she chews/destroys. Yes, she's little, but she still does some damage! She's chewed up a couple of cords necessitating new purchases, plants dug up, chewed furniture legs, and the chewed the corners of our staircase.