Wall groupings are the way to go.
You can buy a number of smaller prints and frame either individually, or put them together into a collage-type frame. This can save a significant amount of money, and the possibilities are numerous.
Need to fill a square space? Buy four smaller square prints and hang them together for a larger area of artwork. Or, buy a square collage frame and fill it with whatever size prints fit the openings. I like buying smaller canvas prints and hanging them together without a frame.
You can do this with any shape you need to fill, vertical, horizontal, or square. I have even seen circular frames with multiple photo openings.
Here are a few different groupings to help get you thinking. Don't necessarily pay attention to the sizes of the prints in the examples; you can make a 16x16" grouping with just four 7x7" prints. Experiment and have fun with it. Cheers!
P.S. I have been working on Polyptychs, which is one large photo of three different photos, if that makes sense. I will soon have a separate gallery opened with some offerings. 🤔