Hello AtariAge!
I visit here often but have never posted before. I also pre-ordered the Retron 77, but I wasn't pleased to read this disclaimer on their product description page:
under list of included items:
6 ft. Micro-USB cable with AC adapter*
Then at very bottom of description:
*If AC adapter is not included, we strongly advise you use a 5 Volt 1 Amp USB wall AC adapter.
I would be most unhappy if the new console I purchased did not include a power supply.