dave1993's $18 micro-quad

Well this is pretty amazing! dave1993 has put together a microquad for $18.  He's posting more photos and details, but here's what I've gleaned from the thread so far.

• control board: V929-06 Beetle, SKU:SKU037759, $13
• motors: 716 coreless brushed, 10 pack for $8.90 specify 1mm shaft as per instructions
• blades: Ladybird spares, SKU:3xSKU036330, 3 sets for $6
• bamboo frame
• motor holders
• Rx is FlySky compatible

More details to come.  Dave says

"I've built 4 of these so far ranging from 6" (1/4 bamboo sticks) up to 24" (1 bamboo stick per arm). the little one is kinda "frisky" and the big one is too floppy so 12" (half stick per arm) seems a good compromise." [that's 12" motor to motor]"

update: Dave says:

"holders are simply small paper tubes held on with polyurethane (gorilla glue) foam. it weighs almost nothing and is as strong as all getout. in the photo you can see this is reinforced with a triangle of wood tongue depressor which is also used for the center hub. the whole frame costs about a nickel and only takes a few minutes of your time.

havent damaged one yet after many many (have i mentioned many?) crashes so this seems to be working out. i learned about the zip tie legs in the v929 threads and that looks like a great idea too. keeps the quad up off the ground on less than ideal surface and also contributes to unbreakability. and holds the motors in too as youll see when i get better pics."

For Spektrum compatibility, you can use a Blade MQX board. It's more expensive, but cheaper than getting a new transmitter.  Here's one for about $36.