I have room for 3-4 pins. Currently all Stern.
I typically buy 1 or 2 new machines (NIB) each year and sell 1 or 2 to make room for the new ones. I usually go with Stern and stay away from the really expensive JJP type stuff.
As my pins are usually Pro, with the occasional Premium, I typically loose an average of, say, $500 each on resale.
So, my net cost is $500 to $1,000 per year, give or take, spent on my pinball hobby.
To me, to spend $500 to $1,000, for a years worth of fun is a screaming bargain! Many people spend more than that in Starbucks in a year!