You know this airplane scenario: Passengers compare notes on how much they spent for seats that you'd think would cost the same. It ticks you off when you find out you've paid the most, doesn't it?

Transfer that discussion to the Student Union Building, except now everyone is comparing tuition. That's right. Some universities -- including those in the University of California system -- are thinking about charging higher tuition to students who major in more lucrative fields -- specifically engineering and business.

• MSN Money's Tuition Savings Calculator

Many schools are already doing it, probably more than you think. Engineering and business are often targeted, but some students in nursing, architecture and music (music??) also pay more. Meanwhile, college costs for all students, including those in California, continue to climb overall as states cut spending and endowments shrink.

"Miss M" at M is for Money, who is an engineer in real life, thinks charging some undergraduate students more than others is a very bad idea.

This post comes from Trent Hamm at partner blog The Simple Dollar.

Note from Trent: This week I’m posting a series of articles on the ethics of frugality. How far can you take things without crossing an ethical line or diving into seriously socially unacceptable waters? I’m recounting some of my own stories and some stories from readers along the way.

"Jane" (we must protect the innocent here, right?) writes in:

My husband has always used this expensive Aveda shampoo for his hair. He says it needs to look good for work. I've always used Suave or Pert and it's worked fine. Lately, I noticed that his shampoo looks almost identical to mine, so when his bottle was empty, I washed it out and filled it with my shampoo. I thought the only way he might notice is because of the difference in smell, but he hasn't noticed it at all. In fact, I've refilled it twice with my cheap stuff. But now I feel kind of guilty about it. Should I tell him? Was this the right thing to do?

There are always two sides to every story. So let's look at them.

Is there no end to the new fees, new rates and other credit card company shenanigans before new federal rules kick in and put a stop to some of their antics? Apparently not.

Get this:

• Citibank on Nov. 30 is raising the variable interest rate on some cards to 29.99% APR, Huffington Post blogger Eva Norlyk Smith said. "The card has a variable APR, so the interest rate, now and forever more, will be calculated by adding 26.74% to the U.S. prime rate," she said. If you pay on time, Citi will reduce the interest charged on your balance by 10%. (That's 10%, not 10 percentage points.) Whoop-de-doo.

Here’s good news for online shoppers this holiday season: More retailers are expected to offer free shipping to capture your business.

Merchants are offering free shipping because they know it catches shoppers' attention, The Wall Street Journal reported, and in a year when stores are competing for shoppers, that’s important.

"Free is very exciting," Dan Ariely, a professor of behavioral economics at Duke University, told The Journal. "Free shipping is not just another discount."

Forget those financial calculations about whether you'd be better off doing the housework yourself rather than hiring it out.

A new study involving 6,877 couples published in the Journal of Family Issues makes it a moot point in our mind (and pardon us while we go find the duster). The Juggle blog at The Wall Street Journal says the study indicates that "for husbands and wives alike, the more housework you do, the more often you are likely to have sex with your spouse."

• Bing: Does your husband think you're sexy?

Wow. That is stunning. The Juggle notes that it's been documented before that women are more pleased with -- and apparently more willing to please -- husbands who do their fair share to help around the house. "But the more housework = more sex link -- for wives, at least -- is a surprise," blogger Sue Shellenbarger writes.

Fire the housekeeper. It's time for DIY.

Whats going on here?

This guest post comes from David Weliver at Money Under 30 and is part of his series for National Protect Your Identity Week.

Talk about serendipitous. I've been planning a post on credit card and ATM skimmers -- jerry-rigged little devices criminals use to steal your card numbers -- and yesterday my brother tells me he spotted one of these suckers at a rest area on the New York Thruway.

He alerted managers, who called the cops, who confirmed it was a skimmer. It just proves that skimmers are a real threat out there. Skimmers give fraudsters easy access to unwitting victims' credit and debit card numbers -- even PINs. Here's what you need to know to avoid these nasty things.

This post comes from Little House at partner blog Wise Bread.

One thing I enjoy about my small garden is the fragrant smell of my lavender plants and the movement of the feather grass in the wind. I have become an avid small-garden and container gardener. In the process, I've also gotten very eco-conscious about what I put on my plants and in my garden.

I began to research other gardening Web sites, specifically ones that discuss eco-friendly alternatives to fertilizers. The nitrogen in fertilizers isn't healthy for the environment. In excess, it is harmful to your soil, and to aquatic animals when the nitrogen-filled water is washed out to sea.

The more I researched, the more I realized that I could make my own fertilizer, or mulch, using my kitchen waste. Not only do I reduce my kitchen garbage, I reuse it to benefit my plants. I also save money by not having to purchase additional nutrients or replace dead plants very often. It's a three-for-one deal.

Be sure to scrutinize your cell phone bill carefully. That “free game” you played on Facebook may come with a $10-per-month charge, writes Steve Alexander of the Star Tribune in Minneapolis.

Alexander writes that most people are savvy about Internet scams that involve giving out your personal information on the Internet, which can lead to identity theft.

They should be equally cautious about giving out their cell phone numbers before they read ALL the fine print. Otherwise, they may find themselves signed up for an expensive “premium SMS,” or text, service –- in essence, agreeing to pay a company to send them advertising.