It depends on the frame. Some are plastic, some are metal, and there are other materials used as well. The descriptions will indicate the materials they are made out of. I've ordered 3 pairs from EBD ($6 and $9 pairs--cheapest there are) and they are excellent quality. An equivalent pair of frames alone from the store would have cost $150+, not including lenses.

I do not know, I am hoping there medal in the frames and not completely plastic. I will find out when I receive them.

Lower prices for me, have proven to be less quality

I ordered two pair and wanted to have them filled at Costco. Costco labs said they were substandard quality and would not refill them. Paid $15 for one pair and $32 for the other.