Clomid (with menopur?)

SF • We have a 5 yo and it took about 4 years of trying for our 2nd, due in July.
I'm trying to decide if I should use menopur or not. I just finished my 5th dose of clomid today. I took femara with no results, except one chemical, for 6 cycles. I have menopur to take. It's $300 per u/s for the monitoring. So, the RE said I might need 2-4 u/s. WWYD? Share your experience! Thx!