So I have no trouble meeting the early deadline for a cheaper fee.

The main way I save money is on housing. I generally do not stay at the recommended hotel. One time I couldn’t find anything else, but once I stayed at a cheaper hotel down the street and twice I stayed at a hostel (they’re not just for youth anymore). Of course if the conference is nearby, you can stay at home.

The other way I sort of save money is to make the trip my fun vacation trip for the year. Often the conference lasts for only part of the week. I take the whole week off and do sight-seeing the other part of the week. This way the transportation for my vacation is the same as the transportation to the conference.

Look carefully at your housing/transportation combinations. For example, when I went to Disney World, I compared flying in, renting a car, and staying someplace cheap to flying in and getting free transportation to the cheapest Disney hotel. They ended up costing about the same, but the latter gave extra advantages like being closer to the park and being allowed to come or early or stay late at one of the parks each day. We also brought some food in our suitcases (nuts, etc.) because we knew we wouldn’t be able to get to a decent grocery store.

I use all your other ideas (though I rarely save snacks) except I usually don’t know anyone else going to the conference to room with me. Another good thing about the conference meals is that it’s a good way to meet people and talk about things and get more good ideas.