Yes, Magic Jack works great and you need to purchase it before you come. You will use it over the internet and it will plug into your router. You can do more research about how this works at http://www.magicjack.com — you can also use Skype on your computer if you like — see more about that at http://www.skype.com. We use both and both work fine.
Once you get to Cotacachi you can decide if you need a house phone or not. We have one since we got a landline as part of our internet package, but we never use the landline and, in fact, we don’t even have a phone hooked up to it. We have local cell phones but rarely use those either. We pretty much do everything by email… 🙂