What Kind?

For starters, there are simple Loop Pedals and there are very complex Loop Stations, and everything in between.

If you are new to looping, I would advise a less complicated single or dual channel looper that has only one or two inputs, and a few selectable operating formats. Generally speaking, a very simple looper will have just one instrument input, and an output (maybe a mono &/or stereo output). There can be one or two built in foot switches, sometimes a selector switch for selecting various types of functionality, and sometimes a port to add an external add-on foot switch for a little more control. There could also be MIDI connectivity for interfacing to Digital gear or for receiving information from other sources

A looper with more than one channel (track) will normally have a selection of recording/playback options and may also have several choices available in regards to what instrument gets recorded (captured) onto which track, and which output jack each of the instruments/tracks can be sent to. This amounts to having a simple onboard mixer built in to the looper.  As more channels or tracks are added, more of these routing options should be made available.

More advanced loopers may begin to include some kind of bass/treble, equalizing control at either the input or the output stage, or both. Then it may also become necessary to also include level (gain) control at input &/or output stages, track level controls, and much more. There are loopers that come with onboard effects, built-in drum machines, touch screen graphic user interfaces, Midi in/out, & USB interface functionality.

Needless to say, prices range from well under $100 US to well over $1000 US. Your $$ budget, technical proficiency and musical needs are the factors that should determine where you will start your Looping Life. No one can make that choice for you, and making an informed decision is your best bet.

In Summary:  LEARN !!