Personally I allow myself around 150€ a month to spend on completely silly stuff and I might blow it all on CC.
Congrats, you won't find anything more silly than blowing 150€ on virtual items. lol
you could as well light up a cigar with the cash, donate to a relief fund or back a project on Kickstarter. All of that would be better use for that amount of money.
and no, I won't spend any real money in the shop. No gambling boxes, no magically summoned carbonite chamber and no useless pet. I'll save it up in case it can be spent on something useful, a.k.a. the damn space expansion, if it ever comes.