Many factors will influence on the price of nerd glasses. The prices vary widely upon the material, brand, lenses and agency. High quality and high tech material of frame will take you more money of course. Different treatment for lenses such as tinting with color or covering a protective film could also increase the price. Some famous manufacturer will make a higher price because of brand benefit and service. You may also find the different price for the same glasses at different store. I recommend you to go to the chain store or outlet to get the low-cost and high-quality glasses for saving money.
Oh, this is really a hard question. Because the prices vary in different shop and styles chic nerd eyeglasses. For some shops, you can get it with less amount of money may be dozens of dollars. But for some brands designer chic nerd eyeglasses, you may need pay for hundreds even thousands of dollars. And as far as i could know, online eyeglasses are average cheaper than they were in real shop. So, just search it online.