I don't recall what my first one cost me (Shimano Alfine + B&M Lumotec IQ Cyo N Plus + B&M Toplight Line).

However, precisely one year ago I built a 650b wheelset with a new dynamo. Got all the electrical components from bike24.net. Here's the cost breakdown:
Shutter Precision PD-8 Disc Hub Dynamo = 78.07 Euro
Busch + Müller LUMOTEC IQ2 LUXOS U Front Light 179U = 92.43 Euro
Busch + Müller Toplight Line brake plus = 21.76 Euro
S & H = 19.95 Euro
Total = 212.21 Euro

Given the favorable currency exchange rate, the total equaled $230 US, which I consider a steal, especially given that the Luxos U light includes the USB charger for the rest of my electronics.
Today, in US, one can not buy the light itself for less than what the whole shebang cost me.

One year later everything still works as intended, and I expect many more happy miles with this setup.
I realize that the SP dynamo would cost me more in the long run, as the hub bearings are not exactly user-serviceable, but I might take the risk and service them by myself when the time comes...