If you haven't done it before I wouldn't go with a cow that's listed as "would make good nurse cow". That's like the ads for a 6 month old colt that "would make good kids horse". LOL. Yes he would - in 5 years or more with tons of work.
When I brought 311 home she was hobbling around on 3 legs from footrot and she still fought and kicked every time I put the calves on for about 2 solid weeks. I had her snubbed, put an anti-kicking device on her, and then I had to stand right there and lean against her so she'd stay put. And she was mad - hated every second of it.
Those black calves are the third set she's had on, and yes, she's good now, but back then - wow.
162 still hasn't accepted those twins. It's been almost 2 weeks now and I usually still have to rope her, or like tonight, she stood on one side of the pen while the calves nursed while I stood on the other with a handful of rocks and made all sorts of threats about what I'd do if she kicked those calves. LOL!
The nurse cows that I've had were cull cows from the dairy. They take a LOT of work, and yes, once they accept the calves I've been able to turn them out together for months and simply grain the cow - which to me is a good alternative to bottle feeding. Calf gets milk for however long I want to leave him on and I don't have to mess with them.
The good nurse cows that are halter-broke, tame, easy to work around and accept calves easily are going to cost you at least $1500. If I had more time and a little less sense I would take on a few cull cows at $500 a head, spend a month or two working with them, and resell. However, I don't have that kind of time for taming down 1600lbs of mad cow that I won't be keeping. The only ones I've taken on were ones I had long-term plans for.
As far as feeding goes...basically I figure I put $$$ into the cow (hay, pasture, grain, whatever), and then divide that cost by the number of calves she's raising at the moment. Calves cost approx $6/week in milk replacer, cow raising 4 calves can't be fed more than $24/week herself or she's costing me (and it would be cheaper to bottle-feed). Up to $24 and the cow is "free", calves cost so much per head per week. To be honest though, it's hard to put $24 worth of feed per week into a cow. Usually runs about $18/week for 311 during the winter so she has to support at least 3 calves or she isn't paying her way. Make sense? 162 gets less grain and cheaper hay because she only has two calves - I can't feed her more than $12/week.