Being the cheap-o that I am, I only bought one maternity item my entire pregnancy. I got lucky because my sister was 3 months ahead of me in her pregnancy, and gave me all her leftover maternity clothes right when I started needing them. Also, I made a few items to wear to church.
First I made a maternity dress. I started with New Look pattern 6068. A super basic dress pattern. I added 3 inches to the front (so I could gather the sides) and a little bit of width to the belly.
When I tried it on it was wayyyyy too big, so I put it on inside out and pinned the sides until it fit correctly, then sewed up the sides. Make sure to use a zig-zag stitch when working with stretchy fabric, otherwise your seam will split open whenever you bend over.
It turns out these "horizontal" stripes are actually diagonal stripes. I didn't notice until after I started sewing the dress. It twists while I'm wearing it because the fabric is draped diagonal from how it should be. This was kind of a nightmare.
I put a slit on each side. You can also see below the dart that I added.
I took a small strip of black fabric and sewed it around the neckline to look more store-bought.
All of my leftover fabric, i.e. basically nothing. I cut it really close on this.
I flew by the seat of my pants on this one I just laid the fabric out, cut it, and added a waistband that was gathered at the sides. Easy peasy.
By the time I made this skirt I had stuffed my dress form to be maternity. This made things SO EASY.
Aaaand I don't have any pictures of the finished skirt. It looks just like this final picture except without extra fabric hanging off the sides (the fabric is reversible, and in the above picture I'm wearing it inside out). And the hem is finished. I also added a 1" waistband at the top.