Often times people ask me why they shouldn't settle for the cheap drugstore version of reading glasses if given the choice between spending $5, $20 or $50. The reason is the quality is often lacking, the power promoted may not actually be correct and as this article explains even the pricing isn't always what it seems to be:

www.mercurynews.com/actionline/ci_13031424?source=email

Pricing aside, materials used for the frame and lenses are often sub quality, imperfections are often found in the lenses and the hinges usually don't hold up over time. I don't like to make sweeping remarks regarding anything, however OFTEN conventional over the counter reading glasses are not your best option for near vision correction.