I'm assuming you're talking about money spent on games. It really varies for me depending on how much is being released. But typically, I spend under $10 a month, which you should add to your poll. I don't buy games left and right anymore because most of them I regret buying, especially the .99 ones.
During the first few months when I purchased my iPod, I probably spent somewhere around $60 per month, but lately it's died way down. I spend somewhere around $10-$20 monthly now.
for the first two months when i got my iPT i was one of those who wouldn't look at an app if it cost anything...but I don't usually spend more than $20/month now
At first I spent nothing on my phone and loaded up with lite versions and free games to get an idea of the capabilities. Last couple months I'm buying more and more. I'd say around 30 a month is a good estimation, but honestly I won't limit myself at all while I'm building a good starting collection. If a game seems like good value for the money and I'm interested, I'm buying it. And if a game offers high replay value, and fills a gaming genre I'm light on, I'm buying it. Once I feel like I've got my phone set up with a nice selection across genres, I'll probably slow down to more "must have" titles.
I try to spend around $10 a month. Gets addictive (and space consuming on my 8GB so I have transfer back and forth sometimes). I always try to hold out for sales, but it isn't always easy if it's something I REALLY want.
Every pay day (for me the 1st and the 15th) I usually buy a $15 giftcard. But for those must-haves that I wasn't anticipating their release I'll put them on my visa. So probably anywhere between 30 and 35 a month on average. It's addicting. I love the instant gratifacation that idevices offer. I mean, I can littlerally be playing a game within 5 minutes of their release no matter where I am.