You could either get a PAYG dongle or set up an account with a company that allows you to switch it off when you aren't there.
The dongle means you just pay for what you use and companies like Vodafone do them. The big Carrefour shops and individual shops do them. You are limited to the amount you can download so it depends what you use them for.
The companies, like dvblab, Ole, Teleast and so on will set up a very small (about 6 inches across) dish for you plus the cabling and router/wifi for about 100 euros. There is then a monthly contract of about 18 to 20 euros which gives you unlimited downloads. You email them when you are going to be away and they turn it off, email them when you are coming back and they switch it back on. No charge when you are not there.
Downside is that they only do full months so if you are there for 2 weeks you pay the full month. I don't know which of these companies cover your area, you'd have to contact them and see (all have websites). We use dvblab which also gives us a landline phone but we are here permanently. I know if you are with dvblab and are here for, say, the last week in one month and the first two in the second, they will only charge one month rental whereas others would charge for 2 months so you would need to check that out.