What is heavier the stock 15 inch steelie or any type of 15 inch aftermarket alloy wheel ?

Depends on the wheel, you'd have to check the weight. Most alloys will probably would be lighter, but there are heavy ones out there.

Anybody ever put their steelies they took off their scion on a scale. I've always wondered the weight of those things.

Yea I'd like to know too!
I'm getting 16" motegi wheels at 19lbs a piece! I'm hoping that will be lighter than my steel wheels! Looking to improve the mileage with lighter "shoes"on baby.
Just got a BBC 08 - shhh!
Howard in Gilroy

Oh , FYI
Lighter wheels can be had - 12-14 lbs but count on about $300.00 a wheel!
like Enkie Feather or Motegi track lites. Midweight 15" can be had at a more resonable cost- check out Konigs"Unknown"(I THINK thats what is called.) or "Incident" Very light . Its a good thing to just go to a dealer and start lifting display wheels! (est 16-18 lbs.)
Howard in Gilroy

FYI, Konig Heliums (we're planning on getting them,) weight 17.1lbs for a 17x7.5 . They're not too expensive as well.

Ok, I just weighed my OEM steelies with the tire. The tire was flat, the monitor was out and no hubcap. The wheel weighed just under 42 pounds. The monitors should only be a few ounces and the hubcap maybe 1 pound so the OEM wheel fully assembled should weigh no more than 44 pounds.

To give you an idea, I weighed my Enkei WDM 18" wheels with the 225x40x18 and it came out to just under 52 pounds. So the 18" cast wheel with wider tires is about 8 pounds heavier per wheel.

The Goodyear RS-A and Bridgestone Turanza EL400tires weigh 20-21 lbs each in the stock 205/55-16 size, meaning the steelies weigh 21-22 lbs each.