You know all those layering tank tops with hidden shelf bras that you have way too much of? The ones that look like these? Well, when you don't want to spend $10 for a set of 3 at Walmart for new sports bras, you can just turn a tank into one. And it's so easy - just one cut and one seam. Here's how:
Turn your tanks inside-out. See the shelf-bra? It's basically just an extra layer of knit fabric sewn to an elastic band that gives you extra coverage and lift. So just cut the whole shirt off about an inch or 1 1/4" below that elastic band with scissors or a rotary cutter, and fold it over the elastic.
Sew that extra inch or 1 1/4" up over the elastic band with a zig-zag stitch. We use a zig-zag instead of a straight stitch because you're going to be pulling this over your head, and if you use a straight stitch that has no give, the seam will pop right out. Don't worry about finishing the edge; this is knit fabric we're working with here, and it doesn't fray in the wash. It simply rolls.
Now you have a whole slew of sport bras that fit you whether you're pregnant or not. They're also great for working out, though they're probably not to be worn alone on those who have been blessed in the chest; the spaghetti straps could cut into your shoulders.
But for me, they're awesome for wearing under low-cut tops. Modesty without the binding fabric around the big belly.