The most commonly accepted method of choosing a low cost electric guitar is to find an instrument with good quality wood, and at least reasonable workmanship. Guitar manufacturers tend to cut corners with cheaper guitars, by using cheaper pick-ups, and hardware, but these are all upgradeable parts. The following are some of the better low cost electric guitars available. (Remember, if you buy an electric guitar, you're going to need to pick out a guitar amp to go with it.
This are one of several Squier models available that offer a pretty good product for a reasonably low price. The pick-ups and hardware are sometimes suspect, and the workmanship varies from instrument to instrument, but for the price, these are a very good beginner guitar choice. The look of the instrument is appealling - Squier Fat Strats are similar in appearance to the much more expensive Fender Stratocasters.
Modelled after the much more expensive Gibson SG guitars, the Epiphone SG G310 keeps it's cost low by using cheaper hardware and lower quality humbucking pick-ups. The G-310 features an alder body, a mahogany neck, and a dot-inlayed rosewood fingerboard. The buzz on this guitar is it's a very good value for the money.
Telecaster. If you're a fan of any of those guitarists, this beginner guitar may be for you. The Affinity Telecaster features an alder body, with a maple neck and fretboard.