I'm not sure the prices where you are at but most places start off at $99 n up but look on line for 3D ultrasounds in your area..
If you already have insurance and seeing your obgyn, he/she may offer that to you around 27-30weeks as a gift to you. I would just ask your obgyn if its offered. I just had my 3D done yesterday , i receved pictures and a home dvd, its just asking for it is all.
Yeah I go to have mines done at the hospital the end of this month with my insurance so you shouldn't have to pay unless you really want it done right away.