Start your HSA now
Great list from Collin. If you're self-employed this is arguably the first saving vehicle you should fund. Tax break when you contribute no tax on withdrawals to pay for qualified medical expenses and there is no time limit. You can pay for something today, hold on to the receipt indefinitely and pair it with a future w/d.
We've had an HSA since year 1 or 2 that they were available. The last few years we haven't had HD insurance so no contributions but a few years of contributing when you're young will compound into a large account balance when you're older.