I said "assuming you are in the 120g range (for 120mm)". It's actually hard to get much below 110g for a size 120, especially not cheap which was what the OP wanted.
The Uno is still around 110g. 10g reduction. It's just a matter of shaving materials. Not much material science or engineering involved.
The stem should be probably one of the last items to save weight.
I disagree here. It really depends on the rider.
A 100kg bloke that's a sprinter? Maybe needs an ultra-stiff, heavy-ass stem, sure. Maybe first that person should focus on losing a little weight elsewhere to start.
A 65kg climber? Does not need a ridiculously stiff, heavy stem. An UNO will actually be quite stiff enough for their needs and I doubt they would be noticing any flex at the stem.
That PRO/CAV stem? It was designed for sprinters. Besides, Bontrager, ZIPP, and even the 'generic' carbon stems are probably just as stiff as your PRO/CAV stem yet lighter than your PRO/CAV stem. They aren't light enough for true weight weenies though.
Last item to save weight: Saddle. But many of us are willing to experiment to a new shape for the sake of weight.