I think it is possible to waste money on formal education. However, you are a case in point of someone who has clearly spent a lot of resources on informal education (financial training, reflection, learning how to blog, etc.). In my opinion, that's rarely if ever mis-spent, because you only do the sorts of things you gravitate towards naturally, or because there's a clear good reason for informally learning something.
There are however, some valid reasons for trying to pay the big bucks to go to an expensive private institution. But if you can't think of them or name them for yourself (or you can, but they're not important to you), then why not go wtih the cheaper alternative?