You will find the 50mg/ml Mexican version in farmacias. Finding the Spanish Primos (100mg/ml) is a bit tricky and may be found in some vets. It's worth looking for, as it can be found for about the same price as the Mexican version.
About a year ago in TJ it was 15 dollars for 3 vials.
But that was a year ago.
I am about ready for a trip since I cant find a source for anything in the states.
And I got a new Mustang Bullet, that needs a road trip.
Never buy primo in Mex. Spanish primo can be found much cheeper from other methods. Personally I think Mexico is getting too pricey for almost all human gear.