smawell, the difference in price can be caused by some sellers selling greater quantities and therefore offsetting the price. The other issue can be inferior components, due to short cuts in the manufacturing. Those components have most likely a higher failure rate as well ( do not last as long). This does not mean that every part is necessarily bad, but you will take a higher risk. Service and warranty also make a difference. Companies, like ifixit, that stand behind their products and offer a warranty and after sales service, are less likely to sell inferior products. The ultimate decision should be based on if you like the product or not. If you feel that your computer is okay with a $30 glass, then I would purchase that.