Problem #1 - The soundcard on your laptop is probably NOT full-duplex. And/or otherwise sucks in comparison to other soundcards. Full-Duplex being the ability to record one track while playing another track. And not have the two bleed into each other. Not to mention that you'll need a good set of closed headphones $30 to $400 to do that anyway.
Problem #2 - If you're gonna get a real mic, you probably need all of the "other" gear. Microphone cable $25, Microphone stand $25, Boom arm $20, Microphone preamp $30 to $2,500.
For what you're wanting, you probably can't beat something like a Zoom H2 or H4. One other option would be a voice recorder $50 to $250. But it'll be difficult to multitrack on most of those. If all you want to do is record the room, just get a giant squid mini mono $15 or something similar. It requires a bias voltage / plug-in power which your laptops mic port probably provides. Otherwise you'll also need a battery box $60.
You might get by with a boom box, or it's modern equivalent. Some of the audio on modern video cameras isn't half bad. You might go that route if you have access to one, and don't have to buy/own it. Download it to the computer, extract the audio only, good to go. Lots of low budget options. But if you want to multitrack, you need a full duplex soundcard at a minimum. Or a multitrack recorder. Then you can start talking mics.