In some ways it may seem to be a little unfair when solo travelers have to pay up to twice as much as couples in some instances when it comes to holiday travel. There are ways for an astute single traveler to keep costs down when contemplating travel overseas, these include;
Hotel Accommodation
Hotel accommodation can be the biggest single expense for solo travelers, meaning you pay the full cost of the room rate yourself. Sometimes the price of your hotel can be offset by dropping your preferred star rating from say 5 star down to 4 four star stay, with little loss of creature comforts.
Another option is by using a home sharing site such as Airbnb to rent a room in someone's home for the fraction of the cost of a hotel room. Another benefit being an opportunity to mix with the locals and gain an insight into the best places to dine and play which is favored by the locals.
Ride Sharing
When arriving at the airport and you are looking for transportation, ask around to see if anyone else is heading in your direction - they would be willing to split the bill with you. In some countries, ride sharing services such as Uber may be utilized saving considerable cost to the traveler.
Flexibility
If you are prepared to wait until the last minute, some group tour companies may waiver the single supplement fee in order to offset a tour with insufficient bookings. These offers are not made available on line, so contact the company directly by phone to inquire as to availability - you never know you might just get lucky.
Food And Beverage
Depending upon which country you are visiting, food can be a cheap or expensive option for travelers. Street food in Asia is one example of a location offering delicious fresh food for under $2.00 per serving. Some parts of Europe offer 'bar food' where a single diner can sit at the bar and choose a meal from the menu at a reasonable cost.
Travel Buddy
If you are considering taking an organized tour or an ocean cruise, its highly likely you will be slapped with the dreaded 'single supplement' adding anything from 25% to 100% cost of the tour. Many companies now offer travel matching where solo travelers can be paired with another on the same tour or cruise.
Do some research before making the commitment, as it may not suit all solo travelers to share accommodation with a stranger. On the other hand, you may meet a friend for life.