If you are really in a bind and need cash, one relatively easy way to make extra money is by donating plasma. I did this twice in November. The first time I was paid $30 and the second time I was paid $40. There are also incentives offered for every 5th donation. The initial visit took a while because you have to go through screening and a physical, but my second visit last less than 90 minutes. I brought a magazine to read while I was donating, so in essence I was being paid to read a magazine.
The caveat is I hate needles. That has kept me from returning to make a third donation. I cringe at having a needle stuck in my arm for an hour or so while the plasma is sucked out of my blood. One problem I encountered is that I have small veins or they are hard to find. It's probably because I am overweight although my arms aren't bigger than the average persons.
The pay varies by site, but you are allowed to donate twice per week. For me that would be $70 per week, $280 per month, or over $3,500 per year.
For now I have decided not to make a third donation. I might change my mind and return, but those darn needles keep me from doing so right now.