I’m going to second (third, fourth, fifth) the Roth IRA recommendation. You can set it up with Schwab or whoever and can make recurring contributions too (set it and forget it) there are income limits so if you are really raking it in one year you can’t contribute that year but whatever you put in there is still (usually) going to grow in value. If you have an emergency situation and need the money you can withdraw contributions, not earnings, ahead of retirement, so it’s not lost to you, but working for you and much easier at tax time, no worries about how to report it.