If under the word "rest" means felting, like a seal, on the beach, then you need to go no before October. In the middle of autumn, just the season for a beach holiday. But do not forget that the season is a tensile concept. For example, you can fly in August (in Santiago will be winter) and relax completely in the thermal waters in the suburbs of the capital of Chile.
As for the cost, then everything is purely individually. It is difficult to say how much money will spend exactly you. But I can write you the average prices for a week for different services. If you try hard, you can find a one-room apartment for 22.5 thousand pesos (1.5 thousand rubles / week), and a two-room apartment is 2 times more expensive. But do not think that everything is so easy with this. To remove the accommodation, you first need to please the owners, for this you, together with the crowd of people who strangely (the same apartments) come to the views. Then the owner of the housing needs more time (usually one night) to think and perhaps you will be lucky and he will choose you as a tenant. What would chose you, you must speak perfectly in Spanish, to impress the owner. Prepare as it should be saved. Removing accommodation in the hotel you will not be able to save the budget, because one day in a simple flavor cost from 25 salts for 2 persons, with shower and toilet in the room. We managed to get acquainted with one man from Canada, who lives in Santiago almost free, he purchases products in the markets, and the apartment got through the tracks of Surf. So there is nothing impossible, it is only worth trying and wanted very much. Do not be afraid to try, no one will punish you for it. It is better to try and accurately know that nothing good will come out of the venture than not to try and then think all the time, but suddenly it would happen.
Maximum for utilities comes out of no more than 6750 pesos (450 rubles / per week). Not more than, let's say, in Russia. We had a case when we accidentally slam the door, and the key was forgotten inside the room. I had to call the masters, I expected him one hour, for half an hour he cut the castle. As early as one hour, he saw a new key for this castle. I had to pay 25 thousand pesos (1500 rubles). But if we talk about punctuality and quality of work done, then the master was at the height.
If you are not an amateur restaurant and there is an opportunity to prepare at the hotel (sometimes some hostels provide such an opportunity) or a removable apartment (the presence of a gas stove), then the products will cost you about 22.5 - 45 thousand pesos (1.5 -3 thousand rubles / in Week). This is also not a bad price at all, given the quality of products. But it costs to buy exclusively in the markets, in Santiago there are several thematic - fish, vegetable, fruit, meat, nothing. If you do not like to stand behind the stove and prefer to eat in restaurants, then your expenses are increased several times. Choosing for you, naturally. In the restaurant, we usually leave the amount for two 25 thousand pesos (1666 rubles), we order 2 hot dishes with a side dish and 2 beverage. In a simple cafe, you are for the same quality dish, but more in size, pay about 12 thousand pesos for two (approximately 830 rubles)
It turns out that it is possible to rest in the capital of the country of Chile, more developed than our homeland, for 45 - 50 thousand pesos (90 - 110 dollars or 3 - 3.5 thousand rubles).
If sometimes a subway or a taxi is used, then for a week it takes about 10-20 thousand pesos for 1 person. Gasoline dear, about 50 rubles per liter, so that in its transport is not at all profitable, which is why we broke up with our Ford Bronko.