Here in Slovenia with Vodafone operator it costs: first megabyte is 4.2euros after first it cost's 0.42euros/megabyte and if you want unlimited connection you have to pay 21€ per month and on Vodafone we only have EDGE/GPRS, for 3G I would have to change operator, but EDGE is enough for now as I usually find Wi-fi, which is now on every other corner as you walk through town.

Best regards, DK