Travel is an essential part of living.
It could be to explore, visit family and friends, etc.
It is great when you travel cheap. and you can also save money on renting a place to stay.
you can check out my post on hostels in Copenhagen. It will give you an idea of what to expect if you would like to stay in one.
BUS
I find that the cheapest means of travel is by bus and many European countries have a bus route linking them.
For example, you can travel by bus from Denmark to countries like Norway, Germany, Sweden etc. 
Upside: They are 25% cheaper than trains. Popular bus services are Flix bus, Netbus.
I have traveled by bus from Copenhagen to Gothenburg. It cost about 300-400 Kr. It was/is not the fastest, but if you do not care about sitting down for long hours, then I guess the bus is for you.
The trip I took lasted about 8 hours.
The bus is quite comfortable and they are usually equipped with WiFi, charging ports and toilets (very important).
During my Erasmus exchange, I traveled 2 hours daily to and from where I lived, to my school with the bus. So for 4 hours a day, I was sitting on a bus everyday.
Downside: There could be a problem with timing, because the buses are not as frequent as the train.
Once, I had to sit out in the cold from 12-5 am at the station for hours because I had an exam to write at 9am, and the earliest morning bus was leaving at past 7am. I took the last bus leaving the city and waited at the station for daylight.
NOTE: It helped that I also had a student discount and could buy a 10 trip card at a cheaper price.
TRAINS
The next and most convenient is the train.
For me, this is the most reliable.
I have traveled to several places just by train. Once I had to meet up an appointment on a specific day and still get back to work the next day. The train was the cheapest and most convenient for me.
I traveled at night, arrived my destination in the morning, finished what I had to do and traveled back that evening.
The hours afforded me ample opportunity to catch up on my night sleep with enough leg space.
There also discounts for students and young people of a certain age. It might mean, you need a pre-ordered discount card so it will be nice to check it before you book.
FLIGHTS
Sometimes I am boujee, and I take a flight. Especially if I plan my trip well in advance. 
Also, my home country Nigeria is not one I can take a bus or train to.
I remember reading sometime ago, that the best time to book a cheap flight are on Tuesdays. It has worked for me ever since. I don’t do weekends, the prices are crazy and definitely not when I am paying.
NOTE: I have heard that Sundays are also a good time to check flights. Haven’t tested this theory yet.
There is also this trick of clearing your cookies when searching I got from a friend.
I create travel fare alerts well in advance on travel sites. I mainly use Momondo but there are others like Expedia, Hotwire etc.
When you create fare alerts, you get notifications in your mail when there are changes in price.
Although I Check for flights on travel sites, I try to go first on the website of the airline before booking.
I find out that sometimes, the flights are actually cheaper on the website of the airline. And you can use bonus points. It is important to sign up as a member to get bonus points.
There will come a time when I can travel conveniently on weekend flights and on first class but till then Tuesdays it is.
One more way to travel that I have not explored is the ferry. I have taken short ferry trips between Islands but never between countries.
Will try that soon and give an update.
Personally I love travel. What is even more better, is travelling for less with comfort and spending money on other things like food.?
Got any more budget travel tips, I would love to hear them.
