DC now has surrogacy friendly laws. As for the cost an agency will be 18-45k, surrogacy comp depends on state and if they are an experienced surrogate/have surrogate friendly health insurance but I'd budget at least 30k for that, but likely more in the 35-40k range. Maybe 5-8k for legal (you need two lawyers, one for you, and one for the surrogate).
Lots of agencies have cost breakdown examples on their websites, here's one
http://www.familyforwardsurrogacy.com/
Texas and California have some of the best surrogacy friendly policies (though California is one of the most expensive comp states). Here's a map covering all US states and their policies
https://www.creativefamilyconnections.com/us-surrogacy-law-map/