People love something that's free. But there's nothing, of course, inherently wrong with businesses charging consumers for services they consume. Some companies, such as Google and Facebook, obtain the bulk of their revenue from advertising so they can afford to give more away for free. Others need to charge in order to pay workers, suppliers, and stockholders.

Microsoft - in an effort to gain ground from suppliers of mobile apps, such as Apple, Google, and Evernote - recently began offering free apps for Apple iPhone users to let them create and edit Office documents, specifically Word, Excel, and PowerPoint. This follows the release earlier this year of the same free app for the Apple iPad. Microsoft also is planning an Office app for Android tablets (an Office app for Android phones already exists). To use advanced features with either iPhone or iPads, however, you need to pay for an Office 365 subscription. This costs from $6.99 to $9.99 a month for home users and from $5.00 to $12.50 per user per month for business users.

Subscriptions like this point to a related trend in the digital world. Companies such as Microsoft make more money when they can get you to pay them every month or every year rather than your making a one-time purchase.

As you might expect, many consumers object to having to continually be opening their wallets. Adobe created a firestorm of protest in 2013 when it made its high-end programs, including Photoshop, Illustrator, and InDesign, subscription only. With one-time purchases, you can skip paying for one or more rounds of upgrades if you want. With subscriptions, you have to keep paying to use the software.

Microsoft Office still is available as a one-time purchase. But it's not known whether Microsoft in the future will follow Adobe's lead.

Some websites, newspapers, and magazines also now charge for access. Many membership websites are for niche audiences willing to pay for information they can't find as easily elsewhere. For example, Ancestry.com, for genealogical research, costs from $19.99 to $44.99 a month.

The New York Times lets you read up to 10 articles a month online for

free. But, beginning in 2011, readers who want to read more must pay for a subscription. Fees start at $3.75 a month.

ConsumerReports.org charges a subscription fee of $6.95 a month, or $20 a year for existing magazine subscribers. Harper's provides the content of its magazine for free online but only if you're an existing subscriber.

Many magazines still provide online access for free to gain advertising revenue, to attract subscribers, and as a service to readers. Others have "paywalls," offering some articles for free, with the full contents available only as a subscription.

The world of e-book subscriptions also has heated up lately. Scribd now offers unlimited access for $8.99 a month to its catalog of 500,000 books, including titles from major publishers such as HarperCollins and Simon & Schuster. Scribd is trying to draw customers away from Amazon's KindleUnlimited, the largest online book player today. KindleUnlimited charges $9.99 a month for unlimited access to 700,000 books.