I get (and hear) such significant improvements to audio with investments in the power chain that I've come to think of them as improvements to the source or amp units themselves. I mention this because it leads to the question which MAY help you to think about your decision. If you look at what you spend on the power cable as an improvement to the amp you're powering, would YOU think it crazy to spend the cost of the amp+power cord on the amp alone, if doing so gave the sound quality you heard from the amp+power cord combination? Forget, for a moment what specific item you're spending the money on and focus on the question: is the sound quality you're getting worth (to you) the money you're spending to get it?
A nice benefit on spending money on separate power chain items (like external PSU's or power cords) is that they can be transferred to, or shared between, multiple audio units. A better PSU or power filtering circuit permanently built into a particular audio unit cannot be so easily transferred and shared. So, there's actually a frugality (in terms of not wasting an investment) to purchasing separate power chain items over having them built into the audio units themselves, and paying more for the audio units.
Now, the original question about what I've spent:
I've spent $300 on a Brickwall Audio surge protector (which I actually purchased for its power filtering capabilities), $200 for each of two Black Sands Cable Violet power cords, $20 for each of three Iron Lung Jellyfish power cords, $7.50 for each of 8 Volex power cords, $125 for each of two STEPS PSU's (one 24V, one 12V), $40-ish for each of three Elpac PSU's, and $300-ish for a variety of rechargeable NiMH batteries and a few chargers for them to provide better power to my full stable of stationary and portable amps. Total Power Chain investments: $1500. Total Amp Purchases (which benefit from the Power Chain expenses): $1400.
So, overall, I'm spending a little more on investments to the power chain for my audio gear as I'm spending on the audio gear itself. If all of my audio equipment got wiped out in a fire and I had to buy it all again, I'd repurchase all of the power chain investments again with the insurance settlement. I just think of the power items as an integral, valuable and needed part of my audio chain.