If you are shopping for a bargain iPhone, you may consider iPhone SE which packs with the latest specification in a smaller size. However, if you mind getting a older specification and budget is your first priority, why not seeking a used or refurbished iPhone 5, 5s or 5c mobile phone instead.
The first advantage of iPhone 5s and 5c over iPhone 5 or iPhone 4s is the future iOS support by Apple. iPhone 5, iPhone 4s or earlier version can only update its operating system to iOS9. Even worst, iOS 8 and iOS 9 currently does not support iPhone 4 or earlier.
In addition, source suggested that users may not get any further after sales support when iOS 10 is going to release this September 2016.
The third advantage of getting a refurbished iPhone 5s or 5c over earlier models is about the limitation on phone accessories you can use. iPhone 4S and earlier version used old 30 pin connector which is obsolete.
So, if you target to shop a iPhone 5s after reading the above analysis, the next question you would ask is where to purchase a iPhone 5s from a reliable trader. Firstly, new iPhone 5s may still be available from 3rd parties both on contract and SIM-free. On the other hand, you can get a refurbished iPhone 5s from a trustworthy supplier. Cellphoneage.com is one of the experienced phone and parts suppliers, which is currently selling refurbished iPhone in Grade A quality. They sourced quality refurbished iPhone from AT&T, DoCoMo and all of the phones are fully inspected to fully working order.