You can do podcasting or multi-track recording without the need for a mixer. If you have a good quality professional microphone (Shure SM58 or better) you can connect it directly to your computer via USB using one of two devices.
The first is a USB microphone cable the SoundTech STUSBXLR10. One end is an XLR microphone connector the other a USB to connect it directly into your computer. You cannot use this cable with phantom power microphones.
If you have a phantom power mic what you need is the Shure X2u XLR-to-USB Microphone Adapter.
I have the SoundTech but I seldom use it. I would think that you would have to be very careful when handling it. If you break it it may not be repairable so don’t break it. Maybe a better idea is to buy the Shure even if you don’t need phantom power. It may last longer.