It was back around 1992 when I took a deep plunge into this hobby.. I had built an RGB projector that went through a few stages as far as blanking and combining. AOM blanking at first, then galvo, the combining went from using a trichroic prism that worked but was very lossy to dichro's.
I had taken all of my receipts together and came to $15k + and this was over probably a 2 year period.. this does not include anything before then.. and now?
I will guestimate I have spent around 5k since then so that brings it to a nice and round 20k for sure.
I am very happy that things became cheaper and lighter.
I got into this hobby almost two years ago, but I have always been fascinated by lasers. Over that time, I've purchased six lasers (soon to be seven) and a lot of accessories, all of which have cost me a total of $650. All of my spare money goes into buying more lasers, and after I get a 5mW green, I plan on building a >500mW ~650nm. That'll probably bring me to a grand total of $850. Wow, this is quite the expensive hobby...
Just went through my PP information and did all the maths from my purchases since August 2010:
Total money spent on lasers: 4531.96
Total money earned on lasers: 1189.93
Net money sunk into lasers: 3342.03
Total money spent on lasers this year: 3240.9
Total money earned on lasers this year: 783.61
Net money sunk into lasers this year: 2457.29
If anyone is interested, my income this year has been 5269.90, my car payments roughly 1380, leaving my total remaining money at 3889.90. Of course this is an estimation, but that means that out of all the money I have obtained, only 1432.61 has been spent on other things, like gas, Mumford and Sons concert, and food.
Hope to see more people in this thread.
PS - Interestingly enough, my previous answer(on September 30th, 2012) was pretty close. Before that date I had spent 828.78 on lasers. Although I also sold 135.04 dollars worth of laser stuff for a net of 693.74. I have done work on my bank account in the last 8 months or so!