Don't fall into the pressure to get your house spot on furnished as soon as you move in. There are a lot of expenses that go into building a house as you already know. There will also be several unexpected expenses.
Buy quality pieces as you go and don't use credit. There is nothing wrong with taking your good old time to furnish your house nicely. Don't fall prey to the no interest scams, etc. They just suck you in and then you are deeper in debt.
I am not familiar with your area but we have bought good pieces from:
Weirs in Dallas and Plano. We found our daughter's cherry bedframe at Weirs. It was priced at $2500 for this huge piece of beautiful furniture, top quality and we paid $400 because it was "too big" for most bedrooms. It was perfect for her room.
We have custom sofa and loveseat from Leather Sofa Company and I highly recomend them... you make the pieces to your specifications. Expensive, yes but you get what you pay for.
We have a custom breakfast dining 84x84 and custom dining set 84x84 (HUGE tables) solid wood hand made from Amish Furniture Company. This is guaranteed for life. If something happens, they will come fix it. If you need it refinished for any reason (say you build another house and another stain would look better, then you pay the $150 to ship it back to the person who made it and it gets restained and sent back to you)
13 yrs ago when we built our current home, we got a very nice and very reasonable Natuzzi leather set for everyday from Dilliards. I never thought to look there and we happened to see a picture in the advertisement. This set still looks great 13 yrs later.
When you buy a cheap piece, it might look nice for a year or so then you are back to square 1. We spend the money upfront on quality and then there is no need for replacement due to wear/tear, falling apart, etc.
Direct Buy is a warehouse which is super high pressure and I understand the prices are not that great when you factor in membership, etc.
Just beware. You can find great things on Craigslist due to divorces, people moving, etc. Craigslist is about the only place you would be able to get "nice things" for cheap because people want to deal.
Dallas is full of great shopping.
Enjoy your new home!!