If you want to buy good vintage tortoise shell glasses at very cheap prices, you'd better look it online to see if you have any luck. Online shops like Amazon or eBay is a good way. Besides, some online eyeglasses shops also good places to collect vintage tortoise shell glasses. As far as know, vintage tortoise shell glasses at firmoo.com and glassesshop.com are sold in low prices. Hope this helps.
If you want to buy vintage tortoise shell glasses at very cheap prices, you can go to the Optical Shop to ask for the information and look them online. Compare the prices and choose the cheapest ones. Under normal circumstances, it's cheaper in the online eyeglasses shops. Some websites like firmoo.com and coast.com are good place to go. Have a good luck.