Few different concepts for different needs: Some are cheaper if you use your GSM in the evenings and weekends but then you pay more for the daytime calls.
Actually I pay even less than those rates; I have a Sonera's (phone company) "Amigo" and I pay much less when I call to another Sonera's phones. They quit selling those cards several years ago but I decided to keep mine.(4.88€/month + 9cents/min).
It's only single freq card (no DualBand) and I was going to change it to newer card but the salesman told me to keep it; I wouldn't get cheaper rates from any operator...
Anyway the 5€/month + 15cents/min is pretty close the average cost of using GSM-phones here.
Oh I also have GPRS data connected; monthly fee 18€ and it includes 100mb of GPRS transfers. I can surf in the web in everywhere in here from helsinki to most northern point of our country by using cellphone as a modem thought speed is only about 15kbps uplink /40kbps download.