Cheap phones are cheap for a reason. With phones, you pretty much get what you pay for. The cost differences usually boil down to low vs. high end hardware such as the processor (CPU), camera quality and amount (capacity) + speed of memory. These will make the difference in life of the phone and quality of your experience (ie. frustration). In the end, you may wind up needing to buy a new phone sooner with a cheap model and possibly spending more by having to buy 2 phones in the same time period you could have just purchased a single good quality phone. Although this article talks a lot about Android phones, the message is the same for any cellphone brand. Read this article for the risks on buying a cheap cellphone.
I love technology and how it enhances our lives! Just think, without the Apollo moon missions, we might not have calculators! Imagine!!