It's like anything esle - you get what you pay for. There are really inexpensive 'beginner's' guitars, but they will be lacking in good tone and action. it depends how serious you are, but if you want to play properly, the rule is, buy the best you can afford.
It also depends on the style of guitar. You can get cheap Yamaha electric guitar starter kits from Argos, but these are of the Fender style. Epiphone do good copies of the Gibson Les Paul. It depends on how much you consider is cheap and who/what it is for.