If you go to a state university, you’ll have less debt and more access to state scholarships/grants. There are a lot of good state MLA programs out there. I’m from MA, and UMass has a great program (did my undergrad there) – $30k in debt at graduation for 3 years, which is about what you’d get for a Master’s there too. They’re really good about on campus employment for MLAs so maybe even less. PA also has a good program, and some of the SUNY schools too. I know CA also has great programs. Where are you located?
If you’ve done your research and really feel like landscape architecture is worth your time, forget about the money. Compared to fields like engineering, it’s a drawback. Truly. Architects are in the same boat, by the way. But you won’t be poor, and you will enjoy your work.
If you want to work in an ecological design firm, those opportunities exist – and tend to end up in the hands of MLA students with BAs in Environmental Studies who do ecological design research with their professors. Some MLA programs are better for different aspects of the profession. I think Cornell has a very ecology focused program, as does UC Berkley and maybe SUNY.