A few cell phone carriers offer student discounts, so check their websites for possible discounts. Also, Best Buy has some student deals (although the selection is largely limited to the house brand, Insignia).
It’s hard to say which company is best for deals, since they tend to be seasonal. In general, if you’re looking for PCs, keep an eye on Dell, HP and Microsoft’s online stores: They often run back-to-school sales.
In terms of general retailers, I’m a huge fan of Newegg, which has been a reliable PC seller since the ’90s. (I still have my order history there from 2001, with all of the parts I used to build my first desktop.) And of course, there’s always Amazon and Best Buy.
If you’re aiming to save money, here are a few things to keep in mind: Don’t be afraid of refurbished items. They’re often significantly cheaper and come with manufacturer warranties. (Floor models could be riskier, since they haven’t been repaired and repackaged.) Also, start using deal sites like Slickdeals.net. Their community obsessively follows discounts, and they can alert you when a particular item goes on sale. If that’s too overwhelming, check out the deals from our friends at Wirecutter. They do a great job of focusing on meaningful deals on products you’ll actually want.