Why Gift Rail Passes Make Sense : Eurail and BritRail will raise their rates Jan. 1., but purchases before then are valid for up to six months.

Looking for holiday gift ideas for a budget traveler? Transportation passes are well worth considering, and not only by parents who can buy themselves some peace of mind knowing that a pass may eliminate the temptation for a son or daughter to hitchhike. This is an ideal time to buy transportation passes for travelers of all ages since many rates will go up Jan. 1.

Rates for the popular Eurail passes, which offer unlimited rail travel in 17 European countries, will rise on that date. However, passes purchased now will remain valid for six months. Here’s how much you can save by buying before the end of the year:

- Eurail Youthpasses are valid for second-class rail travel, and are available only to travelers under age 26. You can now purchase a one-month Youthpass for $470. On Jan. 1, the price will rise to $508. A two-month Youthpass that now costs $640 will rise to $698.

- Eurail Youth Flexipasses (also available only to travelers under 26) are valid for travel on a specific number of days within a set time period. Right now you can buy a Youth Flexipass valid for travel on any 15 days within a two-month period for $420. On Jan. 1, this changes to: 15 days of travel within two months for $474; 10 days of travel within two months for $348, and five days of travel within two months for $220.

The regular Eurailpasses are available to travelers of all ages.

- A 15-day, first-class Eurailpass that now costs $430 will cost $460 on Jan. 1. A 21-day pass will rise to $598 from $550; one-month passes to $728 from $680; two-month passes to $998 from $920; three-month passes to $1,260 from $920.

- Eurail Flexipasses for first-class travel on any five days within a 15-day period now cost $280; on Jan. 1, the price will rise to $291. The nine-day Flexipass, good within a 21-day period, will go from $450 to any 10 days within two months for $496. The Flexipass sold for 14 days of travel within a month will go from $610 to 15 days within a two-month period for $676.

Rates are also due to rise Jan. 1 on most BritRail passes, which are valid for unlimited train travel in England, Scotland and Wales. There are different passes for adults, seniors (travelers over 60) and youths (travelers 16-25).

- The BritRail Youth Pass good for eight days of travel and costing $169 will rise to $179 n Jan. 1; the 15-day version, which now costs $255, will go up to $269, and the 22-day version costing $319 will rise to $339. The one-month version for $375 will rise to $395.

- BritRail also offers its own Youth Flexipasses. A pass valid for any four days of travel within an eight-day period, which now costs $145, will rise to $155 on Jan. 1; eight days of travel within a 15-day period rises from $199 to $219, 15 days of travel within a two-month period goes up from $295 to $309.

- The BritRail Adult standard-class pass for eight days, which now costs $209, will rise to $219; the 15-day version goes from $319 to $339, and the 22-day pass will rise to $425 from $399. The one-month standard adult BritRail pass will go up to $495 from $465.

- A BritRail Adult standard-class Flexipass valid for four days of travel within an eight-day period will rise from $179 to $189; eight days of travel within a 15-day period goes up to $269 from $255, and for 15 days of travel within a one-month period, theprice will rise to $395 from $369.

There are more than 15 different types of unlimited-distance rail passes in Europe alone. Some are for single countries, others for several. Tourist information offices and travel agents can help you with details. Keep in mind that many of these passes can only be purchased before you leave the United States.