Start with your "in state" public colleges and universities. They are generally much less expensive for state residents than out of state schools and/or private schools -- and most of the state universities are of at least reasonable quality. Many (most) major state universities have online options now.
Going to a public out-of-state will probably increase the price tag.
Private schools are usually much more expensive -- and while some are of excellent quality, some private schools are run on a "for-profit" basis that focus more on taking your money than providing you with a high quality education.
It depends on what track you are looking for. For Nurse Educator, The University of Wyoming and Mansfield University in PA are very affordable. Both totally online with clinical/practicum in your own area.