The Malenki Nano is a fabulous and affordable (about $30) receiver+esc combo that works great in fairy weight (150g) and US Antweight (1lb) bots.  Jeremiah Ashbrook (organizer of Michigan Mashup) uses them in his fairy weight overhead saw bot. You can find this build and other 3d printable designs on Thingiverse

This quick explainer video shows how and where to connect the wires if you are using n20s motors for drive and a brushless motor for you weapon.