I was so happy to see that old navy carried maternity clothing while I was pregnant. I found their clothing super affordable especially compared to other maternity stores. The majority of my maternity wardrobe for both of my pregnancies came from old navy. I had 2 pairs of maternity jeans that were extremely comfortable. One had the shorter panel and the other had the longer one which was very useful the bigger I got. I also had some really comfy t-shirts and a few cute dresses. I also really liked the tank tops.
ThredUp is an online consignment store, but if you do not mind purchasing pre-worn items, then this can be an excellent destination for finding affordable maternity apparel. ThredUp is actually the first place I purchased a couple of maternity items from because I could not resist the low prices. They currently have more than 3,000 maternity items listed for sale, and all are a fraction of their original retail prices.