I bought the standard "chicken cutlet" inserts for my dress at JC Penny's ($20)last weekend. They're clear, silicone, and are seperated (not attached to one another at all). I used to have decent sized boobs but my child (love her to death!) ruined them, and they are terrible now lol. I bought these and I stuck them in my dress at my first fitting and they make my boobs look amazing! The inserts are like external breast implants, they're huge, but they don't make my boobs look too big, just the perfect size. I definitely recommend these over the fabric cups that the seamstress can sew in.
They won't be sewn into my dress or anything, it's a sweetheart strapless gown, but the dress is tight enough that they just sit perfectly in the bust. And as you wear them, they get warm and mold to your body and are 10x more comfortable than the foam fabric cups I tried on.