While a Facebook business page is an important way for real estate photographers to connect with and market to Realtors in their area, it is not the best way to show off your portfolio. To show off your portfolio, you want a clean site that's not jammed with distracting advertising. I've seen some real estate photographers who have their domain name pointed at their Facebook business page and don't appear to have a portfolio site that they control. I think that's a bad idea. You should have both.
Your website is a key part of your marketing. It's your brand and will be the centerpiece of your marketing so don't cheap out and not have a portfolio site! For around $150 a year, you can build a top quality portfolio site. It's well worth it! Here are the top places to consider:
These all have strong features to build your real estate business around. Here is an article over at PetaPixel.com that reviews these services in detail. These are all very easy to use--any non-technical person can drag and drop a portfolio site together in a few minutes.