Hi Carl, you can't go wrong with any of the Boss pedals suggested but I can absolutely recommend the TC Ditto. It is very simple to operate and just gives high quality fuss-free playback of what you record.
The volume control is really handy - I leave mine set down a little bit so that once I've recorded a few chords they automatically play back at a lower volume for me to improvise over. Another good use of the looper is for experimenting with the EQ or overdrive on an amp or pedal as you can tweak and listen while the guitar keeps playing.
The ony downside is that it requires a power supply as it's not big enough for a battery like the Boss units. You should be able to pick one up on eBay cheaply. I believe there is a newer Ditto+ with more features but the original one may be all you may need.