What is the cost of the most inexpensive smartphone on the market?
As expected, the least expensive phones were found in developing countries (namely China and India) where low wages coupled with cheap manufacturing provides the ability to both market and sell smartphones with much lower prices and specifications than their Western counterparts. The cheapest phones we found (both at around $30 USD) were the Indian Tymes Y4DT 512 MB Blue, and Chinese Cool 8079.
To answer your question I first sought out pre-compiled articles listing the world's cheapest smartphones. While I did come across a number of resources such as this, most of them were focused on more mainstream phones and did not include the ultra-low-cost models found in emerging markets. I subsequently conducted searches on top e-commerce sites in emerging markets such as Nigeria, India, and China.
After some initial searching I noticed that there were a number of very cheap phones available on the market; however, it was unclear if these were smartphones or not. I therefore limited my search to only those that used Android as their operating system.
In 2016 an Indian company claimed to be starting production on a $3 smartphone to be known as the Freedom 251; however, this never materialized.
On Chinese e-commerce site Alibaba there are some smartphones that are potentially listed as low as $1-2; however, because these can only be bought directly from the manufacturer, I discarded these options as they are likely due to volume discounts and not available to consumers or may be artificially low prices to encourage inquiries.
Based on my research, the cheapest phones I could find were around $30. This was true on both Indian e-commerce giant Snapdeal, with the Tymes Y4DT 512 MB Blue, and on Chinese e-commerce giant with the Cool 8079. I've added the specs for both phones below for comparison.
Cost: 1,999 rupees ($31.44)
Front/Rear Camera: 1MP / 2MP
OS: Android 4.0 (Jelly Bean)
Connectivity: 2G, 3G, Wifi
Cost: 199 yuan ($31.50)
Front/Rear Camera: N/A / 2MP
OS: Android 4.0 (Icecream Sandwich)
Connectivity: 2G, 3G, 4G, Wifi
As part of my research I also came across an African smartphone manufacturer named Onyx that is seeking to launch their own $30 smartphone, further lending support to this being the cheapest price point on the market at the moment.
In summary, the most inexpensive smartphones available on the market today are the Tymes Y4DT 512 MB Blue (1,999 rupees) from India and the Cool 8079 (199 yuan) from China. Both are around the $30 USD price point. They both have 3G/WiFi capabilities and run an earlier version of Android (4.0).