You don’t have to contribute to the economy to get your Dharma on. Most religious texts of most religions are in the public domain because of how long ago they were written, this is true of the texts of Buddhism.
You can find free Buddhist ebooks at the following:
There are also other free books on Project Gutenberg for your reading pleasure.
For specific Sutras you can often just do a search for the name of the Sutra +free +ebook and find it.