PPDO. For the solo voyager, this piece of shorthand-- for "per person, double occupancy"-- is the most hated fine print in travel brochurese. That's because some cruise lines and tour operators charge singles up to twice the advertised double-occupancy rate.

Increasingly, however, operators either choose not to impose the single supplement, or will offer to match "suitable" roommates, and if they fail, charge the double-occupancy rate anyway. Here's a sampling (by no means comprehensive) of some single-friendly travel outfits:

Crystal Cruises (800/446-6620) charges one of the lowest single supplements in the cruise industry, starting at 20 percent over the advance-booking rate.

Norwegian Cruise Lines (800/327-7030) offers solo travelers guaranteed fares on some sailings. The only catch: the line chooses the cabin category.

Boston-based Saga Holidays (800/343-0273), whose tours are popular with more mature travelers, likes to eliminate single supplements or keep them as low as possible. Of the 75 land tours listed in Saga's spring 1998 brochure, 28 have no single supplement.

TBI Tours/General Tours (800/ 223-0266) tries to match singles, and even if they can't, some supplements are gentle: $100 on top of a $999 tour to Beijing.

Go Ahead Vacations (800/ 590-1104) offers a roommate match; if they fail, they charge only half what the single supplement would normally run. Some of their single supplements are low in any case: $195 on an 11-day Turkey tour that costs $1,695 per person, double occupancy.
-- George Hobica