I don't know about adoption - I'd guess about $1k. But please be prepared for the cost of pet ownership. Wellness health (exam, vaccines, preventatives) will cost from $500 to $1k per year. To prepare for emergency health issues, set aside $1k to $3k per year (FYI: some common emergencies cost way more than this). Then there's food, toys, supplies, grooming, cleaning, etc. And if you have to get a pet-sitter or leave them at a kennel, you might be looking at $50+ per day.
I hope you can afford to do it. Dogs are wonderful.