The Internet is the easiest route and might save you some
First, do your research: are there budget airlines unique to the country you're flying out of and where you're headed to? Booking with a budget Australian airline (Jetstar) from Sydney to Honolulu, then an American one from Honolulu to Montreal saved us over $400 each when flying back from Australia to Canada earlier this year. This allowed us to create a thrifty five-day stopover in Hawaii on our way back, which was less exhausting and a lot cheaper! Kiwi.com and AirWander are both great search engine for revealing cheaper routes like this that involve multiple airlines.
also some ways that people tend to forget about like using
look for good deals or even deal with a specific airline