Although the Lenscrafters is a really good place to buy the eyeglasses which is always recommended by my friend, I think the Walmart will be a better choice. The price in the Walmart is suitable. In a word, it will be cheaper than other online stores. And the quality is also fantastic. You could take it into consideration.
Yes, you can go Lenscrafters to buy prescription glasses. In fact, the most important part of buying prescription glasses is eye exam. By taking an eye exam, you can know what's wrong with your eyes and your prescription. Then, your prescription eyeglasses should be made based on the your prescription so as to meet your vision requirement.