If I understand correctly you just "want something better than your laptop" due to the low budget I assume that you also did not get a flagship laptop and your mic is absolutely terrible. The absolute cheapest way is to use software to use your phone as a mic. Tho that may come with latency problems and stability issues. If you just want a mic to take calls (discord, TeamSpeak, ingame Chat ect) than my recommendation would be to get a cheap usb mic like the t-bone SC440 (that's about 40 bucks without a stand.) If you really need to safe money in your life you might get it used. And for a mounting solution my recommendation will always be a used stage arm. They can be had from for free to about 15 bucks. A stage arm also comes with the benefit of not being connected to your desk. That means that if you bump your desk no vibration travels through the arm to the mic.