Did you have one? Yes at 28 weeks (window is 24-28 weeks for bubba to have enough fat on it's frame to be able to get images, but still small enough to move around as the images rely on movement)
Roughly how much are they to have done? $200 & no rebate - we got several prints, DVD of the whole session - and about 45 minutes with the guy
Was it worth the money you paid? most definitely - I am amazed at how awesome the pics were and how much detail we got to see (and how much she was like her pics from the scan - we said at scan she was particularly like 2 family members - and she really is!)
Can you only get them done in particular places? Yes. you have to check who does them and how much they charge/what is included. make sure you go to a reputable place (usually a diagnostic sonographer with this as a "side" business - have heard some horror stories about people paying big bucks for people to do a scan, they wait on pics to be printed - and never get them)