A buyer looking to purchase the cheapest iPhones possible need to first decide if she wants a new or used model, as each carries different considerations. Cheap used iPhones may be damaged or older models, and thus have poor performance. Cheap new iPhones typically come with carrier contract requirements.
Buying a used iPhone is one way to save a significant amount of money compared to buying a new model, which can cost upwards of $600, as of April 2015. However, the buyer needs to inspect any used phone prior to purchase to make sure that it is free of damage or defects. If it does have damage, then it should not be significant enough to affect regular use. Damage such as cracked screens is common among used iPhones and lowers the sale price while not impeding normal use. However, problems such as malfunctioning buttons or motion sensors are more likely to make the phone harder to use and should be avoided if possible.
If the buyer is looking at a cheap new iPhone, she needs to find out if it comes with any contract requirements. Many carriers discount the price of a new iPhone if the customer agrees to a multi-year contract, with penalties for early termination.