I don't keep track of this sort of thing in detail but I usually figure a month-long trip ends up running about $10K. Sometimes probably a bit more, sometimes a bit less. Where that money goes will vary depending on the type of trip. In cities, I usually stay somewhere nice but not top-end which I find doesn't buy me a lot incrementally. Don't usually fly business unless I use miles for part of it.

No illusions this is penniless student budgeting but it suits me.