By Rachel Brahinsky

WE'VE ALL BEEN there at some point: your student-loan payment has gone unpaid for months, the rent's due and you've lost your job, or worse – your kid is hungry and your next food stamps aren't coming for a week. You need cash, and you need it fast. We've found a few ways to help you get it, without breaking too many laws.

Pawn shops

Pawn shops are the people's bank of last resort. Turning your family heirlooms into cash may seem distasteful, but sometimes it's the only thing to do. Prepare yourself to be fingerprinted (police are informed of every loan and sale), whether you are selling your old Gibson guitar or trading in Grandmother's gold ring. It helps if you have the original receipt for your item, particularly if it's a Rolex watch or a laptop computer, both of which pawn brokers assume to be stolen most of the time.

If you pawn an item for a loan, you can leave it for up to four months before they'll sell it. The interest rate varies depending on the size of the loan and how much time has elapsed. For the most cash, stick to watches, fine jewelry, tools, musical instruments, and up-to-date electronics. Some pawn shops deal primarily in jewelry only, so call ahead.

Focus groups

You can make pretty good money spouting off opinions – real or not – about cheese, hair spray, or the difference between IBM and Macintosh computers. Two excellent Web resources are Craigslist (www.craigslist.org; look for focus groups under "et cetera jobs") and Silent Way (www.silentway.com/tips/sf/focus.html), which has a list of 18 research groups that host or manage focus-group sessions for corporate clients on a regular basis. You'll earn anywhere between $30 and $150 for a few hours' work, generally more if you fit into a specialized profile. Our advice: sign up with several agencies for a better chance at getting a call.

Trade in your recycling

If you cull bottles from curbside recycling to trade in for greenbacks, you'll risk the ire of San Francisco Chronicle columnist Ken Garcia – and the SFPD, known to ticket for this activity, which is illegal. People still do it, though, especially in desperate times. To keep it legal, save all of your own recycling and ask friends to do the same. Instead of letting Sunset Scavenger cart it away for you, take recyclables to one of the 20 buyback centers in town; for a list go to www.sfrecycles.org. There's one place where you can trade in paper, but since you have to cart it in by the ton, it's not really practical for most people. Aluminum gets you 77¢ a pound, and plastic brings in 24¢ to 41¢ a pound, depending on the type.

Medical studies

To qualify for medical studies, you generally need to meet specific qualifications. You'll earn cash, but you often need to commit for many months to get your reward. For example, one study asks couples to test a new diaphragm gel for seven months; in return, you get $300 and a host of gimmicks, like movie passes. So it isn't the fastest cash you can earn, but it's an alternative when you're particularly down on your luck.

Many studies are more specialized. The UCLA psychiatric department is currently studying people who have had anorexia and their relatives. You earn $150, and you don't have to go to Los Angeles to participate. To get plugged in, call local hospitals (UCSF often lists studies; this week it's looking for heavy drinkers) and check the classifieds in local papers.

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