mainly to record songs
Just in general - Solo voice or solo acoustic instruments are the most difficult because of room noise & reflections, and sometimes electronic noise. A more “dense” or “complex” mix will help to mask (drown-out) noise.
Try a recording application on your phone. The microphone built-into most phones is quite good, and phones don’t have fans or spinning hard drives that make noise.
Try to find an app that records to WAV (lossless). Then, you can transfer the files to your computer for optional editing/processing. The biggest downside is that it’s a non-directional mic so it picks-up room noise from all directions whereas the sound you’re trying to record comes from only one direction. Try to get the mic in a “good position” in some kind of holder or placed on a soft surface and/or rig-up something similar to what Koz shows with his stand-alone recorder.
Do I need to buy a separate sound card to use this microphone properly?
That BM8000 and similar is sort-of an unknown with strange-confusing specs… It’s obviously built-around an inexpensive [u]Electret condenser element[/u] like a regular “computer mic” (not necessarily a bad thing) with most of the cost going into the housing and accessories, etc. But, we don’t know anything about the other electronics inside and it’s not really clear what kind of connection it needs…
Some people do report good results with these cheap mics. And some of these kits come with a mic stand and a pop filter and a cable that are about worth the cost even if you end-up upgrading the mic.
Stage & studio mics are not compatible with regular consumer soundcards or the mic-input on a laptop. “Good” microphones use a balanced (3-wire) [u]XLR connection[/u]. In addition, studio condenser mics require 48V phantom power. (Dynamic mics don’t need power.)
The most common solution is a [u]USB audio interface[/u] which has the proper microphone connection and supplies phantom power. There are also (relatively) inexpensive USB mixers with proper mic inputs.
Another option is a “studio style” USB microphone (AKA “podcast mic”) similar to the [u]Blue Yeti[/u].
Or as Koz suggested, most solid state audio recorders are very good quality.
My budget is limited
A good microphone usually costs at least $100 USD and it’s usually another $100 or more for a USB interface. With a USB microphone the built-in interface is essentially free. A separate interface almost always has recording level control and a headphone output and sometimes you get better quality (less electrical noise). Some USB mics also have these features.
The cost is “relative”. I grew-up in the analog days and it blows my mind that for a few hundred dollars you can get a set-up that’s better than a professional analog tape recorder. (It’s still expensive to build a soundproof recording studio with multiple microphones, multi-track recording, high-quality monitors, etc.)