Quick background about myself:
I'm a web dev from NC that pulls in $65k/year. I also do Android dev on the side that has brought in roughly $5k/year in the past (the monthly income fluctuates a lot). I'm doing this as a sole proprietor, I have not setup a LLC or anything yet.
I've been maxing a Roth IRA with Vanguard for the past few years.
This year I'm on track to max my 401k with my employer.
At the beginning of 2014 I plan on opening taxable accounts with Vanguard. But first I wanted to check and see what I could do with this extra supplemental income from Android. Ideally, I'd like to sock away as much of the Android income as possible.
So I've heard about SEP-IRAs and Solo 401ks, but I know absolutely nothing about them. What are the differences, limits, etc. with each? Can anyone give me some advice or point me to something to read up on (books, articles, blogs, etc.) as I'd like to try and maximize my extra income the best way possible (into retirement accounts). I'm assuming either of these can be done with Vanguard (any catches with that)?
Thanks!
tl;dr: How do SEP-IRAs and Solo 401ks work?