I am 4 months pregnant and cannot afford to buy any maternity clothing-my husband just doesn't see a need for it and he controls all the money. Does anyone know of a way if there is one I can alter my existing pants? I have a string tied around the button and the button hole to keep them on but this is so painful. Any ideas?

No offense, but your husband sounds like an idiot.
You need a good bra. You can get a nursing one and wear it now, but you NEED a good bra. And if you're nursing, you'll need a bunch of good bras because they'll be sweaty and milky and a total mess a lot of the early time.

You will also need at least a few maternity shirts and a few pairs of pants. There is NO WAY I could have made it throughout my pregnancies in my non-maternity clothes.

You could try a Bella Band. It's a variation on the rubberband through the buttonhole trick, but a lot more comfy and way better looking. (It's basically a giant elastic waistband that holds up your unbuttoned pants.)

You can also go on FreeCycle for your city and see if anyone's giving away maternity clothes. Here in St. Paul, MN, I see stuff like that posted every day. Or Goodwill always has a few things…