If your budget allows it I think it's great to splurge on some nice maternity bras like the hot milk ones - you can feel pretty tired and unsexy after your baby arrives so something that can make you feel a bit more feminine and sexy has its place.
The zodee site has some great maternity bras bit they might be a bit over the budget you have in mind.
When I was pregnant with Yasin I got some nice, girly ones at Target that were well priced.