1. International Travel
For most people, the travel aspect of a vacation doesn't have too many supplements for the solo traveler, but this is no reason not to make sure you get the best deal and to get from destination to destination as inexpensively as possible. The benefit of traveling alone is that if you do want to save money and grab a last minute flight, then you won't feel guilty for inconveniencing your travel partner. In many cases, airlines won't want to fly a plane that doesn't have a full manifest of passengers, so a last minute flight can be a great idea to travel cheaply. It is also worth looking out to see what the local budget airlines have to offer, and booking once you are in the country is often cheaper than booking before you set out if you are traveling to different parts of the country.
Flying isn't the only option for international travel, and for many journeys between neighboring countries, taking a long distance bus is often significantly cheaper than a flight, while the travel time to the airport and waiting time at the airport can mean the bus won't take too much longer.
2. Domestic Travel
The rule of thumb here is that buses are generally cheaper than trains, which are usually cheaper than taking an internal flight. It will often depend on how you plan to travel, and there are some areas such as Central Europe where booking ahead of time for a train ticket can be up to three times less expensive than buying a ticket on the day. South America is well known for its colectivos, which are a small mini bus or pick up truck with seats in the back where short journeys are catered for very cheaply, but it can mean a little wait as the driver sees how many passengers need to make the journey.
There are also many countries where hitch hiking is a free form of transport that is quite well known, and those traveling solo have a much greater chance of getting picked up than a group of people.
3. Accommodation
This is often where solo travelers do tend to feel the brunt of higher prices, and not being able to share a hotel room with a partner can make it feel almost twice as expensive to travel solo. One useful way to find cheap accommodation is to find a bed in the local hostel, which doesn't have the single occupancy premium. Those looking to get around on a budget will find couch surfing is not only a great way to stay somewhere for very little money, but also a nice way to meet someone.
In some countries such as New Zealand and Australia, there is also a culture of working for lodging which is a great way to get a taste for the culture of these countries by meeting the locals, and also to save money while still getting to explore the region.
4. Food
A benefit of traveling solo is that most people feel less pressure to go out to a restaurant for a meal every night, and for those staying in a hostel or self catering accommodation, buying groceries and cooking is much cheaper than eating out. Nonetheless, eating the local street food that is available from local vendors is still likely to be a very cheap way to get a taste for the local cuisine on a budget. Eating out alone doesn't have to be a disappointing experience when traveling solo. A positive attitude and an enthusiasm for the destination can make it a great opportunity to engage with locals and to get a real insight into the culture and cuisine.