For quick, cheap and pretty good quality I have used a Olympus digital recorder (VN6000, $40USD) with a plug in ear-bud mike (TP7 - telephone recording device, $15). The recorder weighs next to nothing and the ear bud goes in your ear (duh) under your headset and records everything you hear and say. Records several hours and is downloadable straight to your PC or laptop.
Well under $75 USD from Amazon and you are away!!