Not sure it's worth jumping through all those hoops to save probably not enough money. Keepgo has reduced the price of their 1GB
all-over-the-world simcard to just $59. Yes, it includes Peru. If you run out, 1GB is $45, 3GB $99. You can, with some trouble, absolutely find cheaper cards locally. You've just got to figure out how much that trouble is worth. Given that these cards are active for one year, so you can use it on multiple trips, I think this may be the route I go in the future.
I've used their simcards before, when the company had a different name. They were quite a bit more expensive so I moved away from them. At these prices, I think it makes sense for quite a few people who would rather be seeing and doing things instead of figuring out how to buy a simcard and make it work.