$137.5. I honestly had no idea how high it would be, but I've always been a bit careless with money when it comes to shrapnel or similar amounts. Those $2.50 purchases add up!
If someone wants to spend thousands of dollars in microtransactions, I can understand that. Paying to consume media, ala Foxtel as someone mentioned, paying to customize something trivial or paying to consume something tangible is all the same to me. I'll never pay $2.50 for the chance to win an unusual hat, pokies payout or anything though - I try to always use logic in my approach and theres no way around the crazy logic there!
Now, if I analysed how much I've spent on only slightly interesting games during Steam sales - that would be much more painful!