Casual Conversation

The most commonly recommended USB interface is Focusrite. Cheapest is to get a Behringer or similar brand.

My opinion: For a home studio, any interface will do fine for recording demos and practicing or just getting into it. If you ever become successful enough that you need to record better quality, you should go to a real studio anyway. There's really no reason to own expensive gear unless you're into owning expensive gear..

The normal interfaces are usually capable of live monitoring. You'll want live monitoring for practice and because the latency from the recording is too long to also use for listening while recording regardless of how low it gets.

The limitation of a cheap standard interface is that they usually only have 2 inputs, but it is sufficient for guitar and vocals, and it's usually not necessary to record more than one input at a time anyway.

Personally I do not have an interface. I use a USB mixer instead , because I have more instruments hooked up at once. There is a trick to set this up up for live monitoring, so I'll skip the details, but just to let you know that you might need more than an interface if you want to hook up more instruments or microphones eventually.