You can do an individual 401k. There is a little bit of additional paperwork, but it has some additional benefits over the sep-ira, like income deferral that is not tied to the percentage of business profits. If your net business profits are less than 260k the individual 401k is a better plan. If you make more than that it won't matter, because you will be capped at the same 51k for either one. Easy to open through fidelity.