You can save some of your hand-me-downs clothes, which you feel a bit too big for your normal body. You will be able to use these clothes for the first few months, when your belly will be expanding slowly. However, you will not be able to use these clothes near pregnancy and days after pregnancy, the slow shrinking period. Keep these clothes in a place where they do not get in the way of your normal clothes.
You can also separate the clothes that perfectly fit you when you have normal figure. If you find any long shirts, set them aside. Moreover, you can also look for trousers that sit lower on your hips. You can wear such shirts and trousers in the early months of your pregnancy.
Ask your friends who were pregnant in the recent times. You can borrow their clothes, which they used during their pregnancy period. You can also ask a friend who is currently pregnant, and can share her clothes right after her pregnancy. For instance, if your friend is 7 months pregnant, then you can ask her about her clothes that she used in her early months. This way, you will be able to save a lot of money, rather than buying expensive clothes just for few months.
If your partner is bigger than you, then you can also wear his clothes. You may not find the clothes perfectly fit for you. However, you will definitely feel comfortable in them.
You can wear your normal clothes in the early months. However, it is advised that you should keep them away, and choose from the ones you selected for pregnancy. It will help you make proper decision on what to wear and what not to wear.