I use my iPhone for my main playing and I have a 3G connection for my mac with bluestacks.
I only get 2G a month for everything I do on the mac so i watch what I do like a hawk.
I've found out that normal game play generates little data. I dont play it every hour but I
play it every so often. I also play World of Warcraft on the computer as well.
What I would do is pull up your data monitoring tools (You have to have them if they limit you to 500mb)
and write down (or reset your running totals) and then play normally and after an hour or so before you
start up again, read out the totals and that will give you a fair idea of how much you use per hour.
How much you use compared to me will vary on how many neighbors you visit (I have only a few on my feeder town)
and how much detail it has to download / how often you play (once a day).