I started with a SEP-IRA years ago since the limits are much higher (~20% or 25%) than with a regular IRA ($5k). When the Solo 401k came out I got one of those

I started with a SEP-IRA years ago since the limits are much higher (~20% or 25%) than with a regular IRA ($5k). When the Solo 401k came out I got one of those as well as the limits are even higher than with the SEP (100%). The main catch with the Solo 401(k) is that you have create it before the end of the calendar year whereas with the SEP-IRA you can create it up until April 15th.