Hello Rachel
Welcome to BP, it's always nice to see another Marylander join in.
I agree with @Ophelia Nicholson that the furniture does not have to be expensive. The purpose is to show a prospective buyer what can be done design-wise with the house. As long as the furniture and accessories fit the style of the house, i.e. contemporary, cottage, etc., the stagers have done their job. That being said I do not see many houses staged in my area with the exception of high-end real estate. I'm sure there are exceptions.
Now the flip side of the coin. Staging is fun if you're into the design element! It adds a personal touch to your rehab and surely will leave an impression on potential buyers. An expensive venture initially though, as Ophelia said, collecting pieces over time. You will need someplace to store couches, chairs, tables, bedroom sets and so on and the labor and vehicle to move all of this around. And if you're like my wife, that collecting never ends :) It's all about what you want to do. Many flip investors buy, rehab and sell as a production line to maximize profits. That's fine. If your passion is to take it to the next level, then so be it. Just make sure you make some money in the end!