There are reports from people who have successfully obtained the drug, and from those that haven’t. Towards the end of 2011 it seemed it was increasingly difficult to obtain the drug over–the-counter in Mexico, although by no means impossible with persistence. In 2012 Peru seemed the country of choice for obtaining over-the-counter Nembutal.
They also mention a source in Mexico which has had generally positive feedback, where veterinary Nembutal can be purchased over the internet (for around US $450), although 10-15% of deliveries are said to be intercepted by customs.
It is also possible to obtain very pure powered Nembutal from China via a number of mail order sources. It is generally sold in quantities sufficient for two people at around US $1,000, and simply needs dissolving in water to be used.