Here is a good site: http://www.wheelweights.net/
Lots of wheels, both aftermarket and OEM are listed there.
I didn't see the 9th gen Corolla or current Prius listed on there - but I would guesstimate somewhere around 17lbs for a cast alloy, around 18lbs for a steelie. They listed a Matrix steelie at 18lbs, my Matrix OEM 16" alloys were around 17-18lbs.
As for aftermarket wheels vs OEM - depends on the car and use. Can't really go wrong with OEM, fitment, proper logos, many if not all are certified by some testing lab (DOT, TUV, JWA, etc.) - at least all the ones I've ever seen on OEM. Doesn't mean that aftermarket wheels, DOT approved or not, is poor in comparison to OEM. You could find aftermarket wheels (DOT approved or not) that are superior to OEM in weight, tolerance, strength and durability. Then again, there are ones that couldn't hold air for a give point of time and would get out of round in a heartbeat.
For aftermarket - I tend to stick with bigger, well known name brands - any type of certification, a plus. Doesn't mean other aftermarket wheels are inferior - I just feel better riding on a well known brand. Many of the well known nameplates are manufacturing lower priced point variants to flesh out the entire line of wheels. Just like big name tool manufacturers market lower cost tools and market upward to the premium name.
EX. Home Depot's Husky Tools are made by Stanley. Sears, Matco, and Allen are made by Danaher. Lowes' Kobalt Tools used to be made by Williams Tool which was part of Snap On but now made by Danaher.
BBS was doing the same thing and helping other companies like ASA Allow Wheel company (a subsidiary of HANKOOK Tire Co) with technical input from BBS Germany. Doesn't mean that ASA is made by BBS, but they make a pretty nice wheel for the price. Sport Edition is another - engineered in Germany and built through a subsidiary or Kosei (a pretty decent Japaneses wheel company). Though given a choice between - say a $100 ASA or Sport Edition wheel vs. a $150 Enkei or Borbet to a $250 O.Z. wheel - I would spend the extra money and get the "better" wheel.
One time I violated my own rule and got a set of cheap wheels - looked good, but I ended up trashing three out of four (bent wheels during daily driving) over a 1 year period. Doesn't mean the premium ones are bulletproof either - I trashed a lightly used SSR wheel ($350+) on a road coarse - just cracked on me. Still held up the car, but the crack was readily visble and could potentially let go at any point.