Recording practice sessions

I am looking for suggestions about the best way to record my practice sessions so that I can improve my playing. I have tried using my iPad and iPhone,  but the sound quality is poor-- OK for voice memos, but not music.  Are there good microphones to plug into IOS devices that won't break the bank, or is it better to get a standalone recording device?  I get confused looking at the options online, since I am not an audio engineer.  I don't want an elaborate setup.  Thank you for any help you can offer.