Getting something "free" causes an unusual spark in a consumer's brain, consumer behaviorists have shown.

That might explain why consumers fill out forms, giving up personal information, for the chance at winning something free in a sweepstakes. They will diligently clip supermarket coupons and match them to store sales to get a free stick of deodorant. They will act like lunatics on television game shows for the chance at winning free money or prizes.

That makes it all the more odd that consumers nowadays pay for so many things that used to be free. Sometimes, they voluntarily pay.

We pay for TV service, air for our car tires and checked airline luggage. We even pay extra for drinking water. Pizza delivery charges, street parking and fees for access to news websites are more common. We used to walk or run outdoors; now many pay a fitness center to be a pedestrian on their treadmills.

The point isn't to altogether avoid spending on formerly free stuff; sometimes you have no choice because of marketplace changes. Rather, the idea is to spend money deliberately, determining whether something is worth paying for. That's fundamental to spending smart.

Here's a sampling of stuff we pay for that past generations might not have: