You have a wide selection! Are you interested in something the girls are going to play with for years if they want to, or something you'll dispose of when they get tired of it?
Barbies are tall dolls and their houses take up a lot of space. But you might find a good sale this time of year, or even a good used one (it never hurts to try Craigslist or eBay).
It's something of a gamble any way you do it. But when one of my granddaughters was five or so, the thing she really, really wanted for her birthday was a doll house. Some of her relatives went together on a Plan Toys doll house - wooden, good quality, pricier than many - along with a doll-house family and three rooms of furniture. I think I ended up ordering it on eBay because the price, even with shipping, was the best I could find at the time. Since then she has been given other furniture and household items for Christmases and birthdays. She's eight now and she still loves it.