I don't know about Mexico specifically, but in general, IVF outside the US is cheaper but also less successful.
Avoid IVF and surrogacy in Ukraine. Ukrainian centers pay shills to post here under numerous sock accounts pretending to be patients in Ukraine. Centers using such deceptive advertising cannot be trusted and should be avoided.
I know there is a women from San Antonio, Texas who recently said she was going to Mexico to do an IVF. Her sign-in name is: lost_my_baby ... you can probably locate her on the IVF forum site. She might have more information for you.