The author, where you "sit" together?
If the laptop and the modem, then you should see "dial-up" fares, they have each operator, and then decide, is more important than speed, price, or bezlimitnogo.
If from your phone, Megaphone is the option, which for 210 rubles will give unlimited Internet using Opera Mini for a month. MBS is the cheapest "toll" rate — O hard, 3.50 MB