As we all know that arduino is an AVR chip with Arduino bootloader flashed in. So in fact in order to develop Arduino based projects you don’t need an Arduino board with all that magic wrapped around. Anyway single AVR chip isn’t going to work in most cases. You will need a power regulator, programmer header , crystal and several passives to make it work. If you don’t want to spend several bucks for Arduino boar and yet want to have breadboard friendly Arduino, you might consider ArrDrwonHo converter. This is nothing special – just a simple small board that comes on top of AVR chip on breadboard and brings all is necessary to flash and run Arduino programs.
ArrDrwonHo brings a power regulator that accepts DC from 7V to 18V. Also here you will find serial pins ready for connecting USB to Serial adapter, ISP programming header, 16MHz crystal, power LED and few passives. PCB is designed to be easily built at home labs with hole through components. It great choice for fast prototyping on low budget.