Selling veggies for hundreds of times what you paid for seeds sounds good until you realize that "hundreds of times" is still only $20.00, LOL. I'm not knocking it, believe me, its what I do, I'm just making sure that the reality of that statement is there. As for reality, we planted 54 lbs of garlic seed (i.e. each "seed" is one clove...) last year and only harvested 60 lbs. That would be considered a total crop failure. Each seed should have turned into a head of garlic that weighed a quarter of a lb or so, depending. So 54 lbs should have turned into over 200 lbs of garlic. We do have garlic... its just not what we were expecting. A long cold wet winter caused a crop failure. THANKFULLY we didn't pay for most of that seed, it came from our garlic heads that were grown the year before. We'll move the field and try again next year.
As for making money quick, you might want to check out a website called care.com which is geared towards odd jobs like running errands and pet sitting. I didn't have much luck in this area, but a cousin of mine had good luck with it in GA. I have started farm sitting for friends, but pet sitting is also really popular. Dog walking, etc. If you're going that route, you might want to try to hook up with a rescue and volunteer a little bit (networking, building trust) and ask to post flyers or something in the area. Stop at your local farmer's market and ask any of them if they need help. It might be a drive, but it could mean food and/or money in exchange for work.
Putting yourself out there is the key to getting odd jobs. Its tough, and not fun, but it is doable.
If you've got a reliable source of internet, then amazon's mturk.com is a good way to earn money for taking surveys. It doesn't pay well, but it all adds up over time. You and your wife could do that, and having the money available in your amazon account is really helpful for some of those online purchases that you don't want to pay by the credit card.
Best of luck!