I think it varies widely. My kids are teens now and I get two hotel rooms - but we never stay any place fancy. I bargain shop for airfare. Last trip was over summer 2018 $450 to Europe (out of DC area, into London, flying home from AMS) x 4 people. VRBO in London was about $1000 for the week. We did tours or paid admission to places most of the days of the trip, plus subway passes, and ate out one meal per day. Took train and ferry to the Netherlands and stayed with relatives, rented a car. Total trip for 4 came to about $5000, maybe a bit less. We did one expensive tour that took us to Stonehenge and Windsor Castle.
Anyhow - hunting down inexpensive airfares can be done. Sign up w/ the airlines (Wow, Norwegian Air, etc.) and with services like Travel Zoo, Fare Finder, etc. Use Skyscanner and Google Flights. The more flexible you are able to be about travel dates, the easier it is to find low fares. 90% of my travel is in the summer and if you start looking early and have date flexibility you can find pretty low fares.