Amazon e-book...Mobipocket?

[OneGrassRoot]

I'm researching how to get an already self-published book into e-book format. I see Amazon purchased Mobipocket and that, more than likely, this will be the only format supported through Amazon. That may already be the case.

I read that Amazon charges $150 to get a book converted to e-book format; I went to Mobipocket directly and see the download, even for the publisher's edition, is free.

Anyone have any experience with this? Is there any reason one can't download the Mobipocket format to convert to e-book format and then have it listed with Amazon, without the $150 fee?

Many thanks, and I apologize in advance for my ignorance....lol.