Hellobee Boards

I'd wait until after your baby is born to actually get fitted for one. But if you absolutely want one before, bravado makes good ones that can accommodate several different cup sizes and although they are not the most flattering, they're not bad either. I have 2 of their seamless silk ones and they are so comfy and don't look too bad under work clothes. The band size is pretty accommodating too. i shrank down to my normal band size pretty quickly postpartum. But I was in nursing tanks for the first month at least, they are so much easier than nursing bras.

I bought mine at about 7m pregnant. The cup worked great but the band was tight sometimes (when my breast were full) so I bought a bra adjuster.
It's like an extra extender for the band of the bra & looks like this:

I bought one from Target a few weeks before LO was born, but as soon as my milk came in I knew it was not going to work. The best thing I ever did was go to Motherhood Maternity. They measured me and got me what I needed. Their prices were extremely reasonable and were actually running a sale when I went in. I ended up getting 2 with underwires, and 2 for sleep. I love them all and they have held up great. They still fit 7 months out. Nursing tanks didn't work for me because my boobs have gotten huge! I went from a C cups size pre-preggo to an F cup size! Yikes!

Another vote for wait! Go with tanks until a month or two PP. if you have amazon prime or mom nursing bras h e free returns so that's how I shopped for mine. My target bras are junk and stretched out after a few washes, the bravado bliss is well worth the money. I liked bravados silk bras too, they have a bravado basics cami at target that's cheaper and works well.

@marionberry: I would say get fitted at a high end/speciality store, rather than a victoria's secret or motherhood maternity type store...maybe nordstrom's? Then once you have your correct size, you can purchase wherever you find the best deal! amazon sells some nursing bras for good prices.

I bought a couple of cheapies before she was born just to make sure I had SOMETHING to hold the girls up prior to her being born (I'm super busty and need a bra). Nursing tanks don't support me much. After she was born I went to a LC like @mediagirl and she had a decent selection of bras. I also went to a proper bra store and got my FAVE nursing bra fitted. I still wear it even though DD is weaned because it's such great support.