If you get a $20 gift card for your birthday, the odds you will use exactly that amount on a purchase is slim. Many might spend a buck or two shy of the value and, over time, forget they have the card or lose it. Retailers love it when that happens. And while you may not think of them as such, those rewards points you rack up with credit cards are also really "use it or lose it" money. A study earlier this year by Plastic Jungle, an online marketplace for buying and selling gift cards, said about $90 billion in gift cards are sold a year and as much as $30 billion of that value goes unused. States, as they do in tough fiscal times, are increasingly trying to stake their claim to those unused balances as though they were abandoned property. In New Jersey, for example, legislators passed a bill last year allowing the state to seize unclaimed gift card balances after two years of inactivity (travelers checks and money orders go into its coffers after three). The move, expected to add $80 million to the budget, is on hold with legal challenges. Retailers themselves, when they can, add unclaimed gift cards to their bottom line, itemizing these funds as "breakage." Loyalty programs are another way many lose money without realizing it. According to research released in April by Colloquy, a publishing, education and research firm focused on the loyalty-marketing industry, Americans accumulate approximately $48 billion in rewards points and miles annually. The study, billed as the first-ever on the perceived dollar value of loyalty programs, found that out of the billions of perceived value in reward points and miles businesses issue annually, at least one-third ( $16 billion) goes unredeemed by consumers. Put in perspective, the average household active in loyalty programs earns $622 a year, but does not redeem $205 of those rewards. "That's enough to buy an airline ticket, purchase a week's worth of groceries or even a smartphone," the study says. -- Written by Joe Mont in Boston. >To contact the writer of this article, click here: Joe Mont. >To follow the writer on Twitter, go to http://twitter.com/josephmont. >To submit a news tip, send an email to: email@example.com.