Microphone for android phone (HTC one m8)

I need to record some videos of me talking on my phone. Does anyone know of a relatively cheap way of achieving this that would be a better quality than the mic on the phone? Is there a way of connecting one of those 100 baht USB mics to my phone? Does anyone know what the quality of those is like? What about a mic that would plug directly in to the port on the phone? I'm open to any suggestions here. This sort of thing is way outside my area of knowledge. Oh and I'd like to buy the stuff I need in chiang mai if possible. Thank you