When travelling Chile or another country in South America for a longer period of time, it makes sense to get a local phone number, even if you just use it for 4G (whatsapp, instagram and the sorts). There are different providers you can choose from. I will only mention movistar in Chile on this blog post. If you are interested in other options, check out this useful link.
Movistar
Getting a new number meaning buying a sim card is easy enough. Go to a local Movistar branch and ask for a sim card and a PrePlan. there is no need to register your personal information.
The Sim (new number) itsself costs 2000 pesos in Chile and then there is an additional fee for the prepaid balance. Afterwards you can activate the balance by typing *303# and calling. The PrePlan costs are as follows:
You can always buy additional balance at every store that allows recharge of movistar. For this you have to give the clerk your number and the balance will be uploaded to the numbers account. By going to the website http://m.mvch.cl you can then activate the balance for the wished PrePlan value. Alternitavely you can download the movistar App that allows you to manage everything, it's really easy to navigate. Be sure to recharge the balance before using all your data or keep some inactive balance on the account, otherwise the number will be cancelled after the PrePlan runs out.