Nice find on the promo codes. That one expired, but I used 12OFF, and got... 12%... off.
Grabbed a few of these VLM60W/48V for $3.83 for 60W, no dimmer, two prong input. 93% efficient.
These Autecs constant current 590mA too... $8 for 60W, dimmer, three prong input. 92% efficient...