Credit Card Sign-Up Bonuses – This one might not seem like a source of income but ever since I discovered how lucrative churning credit cards can be I consider it part of my income. Just last year alone, I made over $10,000 tax free in travel, cash and gift cards from various sign-ups. It’s not as simple as just signing up for a card though, it requires a lot of research and some maintenance every couple weeks.
Portfolio income can come from multiple sources – interest/bond coupons, stock dividends, financial strategies including derivatives and capital growth.  Each offers some cash flow and some also offer potential capital gain with some risk from liquidity and volatile prices.  In this low-yield environment, many investors rely too heavily on cash flows and to pursue this are venturing further into riskier areas than they’d normally consider.