A while back I did some research on some lower cost microphones that had really good sound and response. I ended up getting a matched pair of Rhode M5 mics, which worked really well. They are well regarded by musicians for general recording. By coincidence, I also used Focusrite 2i2 for mic interface, since these mics require phantom power.
If you want to step up, the Rhode NT5 are excellent and also include a really nice case. They are over twice as expensive (but still under your $500 limit).
If you want to step up, the Rhode NT5 are excellent and also include a really nice case. They are over twice as expensive (but still under your $500 limit).