Need advice of shopping online!

[children eyeglasses]

I am planning to buy a new pair of prescription eyeglasses, but the price is really high, I am not a rich guy who can spend hundreds of dollars on just a pair of eye wears, which may go out of style in just several months, and these glasses are available in varying quality as well as different prices. I know that I must evaluate the quality of glasses before purchasing them carefully. Who can give me a piece of advice on how can I pick up a perfect pair?