Amazon is having a big sale on some Terry Pratchett e-books. THIEF OF TIME and UNSEEN ACADEMICALS are $0.99; SOURCERY, GUARDS! GUARDS!, REAPER MAN, NIGHT WATCH, and GOING POSTAL are $1.99. (So is THE LONG MARS, the third Long Earth novel co-written with Stephen Baxter. Caveat: I didn't find the first two all that wonderful.)
Several others are $3.99, but eReaderIQ suggests that's not a discount off the usual price.
"People who write poisonous things about your work are using up precious moments of their life dwelling on yours. These are moments they will never get back. Let that be a comfort to you." --Chuck Lorre
+Paul S. R. Chisholm Whatsapp voice calling is relatively new (~6 mos in general release?), not sure of details, but would not be surprised if it worked quite well (it's sms feature is super popular outside the US). There are others (skype of course) and talkatone (part of ooma). You are correct: Google hangouts isn't (easily) permitted via Mexico telecoms. https://support.google.com/hangouts/answer/1267644?hl=en