Arduino Pro Mini Atmega328P-MU (5V-16MHz) board
[VT-DEV0380]

this is a wow product shamik da never discntinue it ever it is the cheapest and the best of all and direct compatiblity with arduino (those who read this should know his has aon chip bootloader and can directly be programed with cp2102 or any cheap ttl uart module with dtr pin (ch34041 module or pl2302 module as well works good , user who wnat to program it using a spi can use their usb asp cheapest