PCOS/Clomid advice!!!!!!

Hello ladies! I need some advice. I went to the OBGYN today because my cycles are irregular and she did a pelvic exam and scheduled a ultra sound for Monday to check for cysts on my ovaries. I am 21 been TTC for over a year and yeah I'm overweight. So she's pretty sure I have PCOS. I've also been on Metformin 500mg since September. She said after the ultrasound we will discuss Provera for starting my period and Clomid to release an egg. My question is how many of you have done this and gotten pregnant? Also is t very expensive???