Should I get a 3D ultrasound??

Emmie
So here is my situation...
I'm not strapped for cash so the $100 to have it done won't be a huge deal but I am also pretty picky with what I spend my money on. I paid for an ultra sound at 17 weeks to find out his gender early but it was only a 2D one because he wouldn't be developed enough at that time to make the 3D ultrasound worth it. Then at 20 weeks I had another 2D ultrasound at the hospital so they could make sure he is healthy and developing correctly (which he is!!! 😊) 
Well, I miss seeing my little man but I just want everyone's opinion of having a 3D ultrasound done? 
Also, can you have too many ultrasounds? Can it be harmful and should I only do it if necessary?