Full texts of 1.7m words of random samples from the COCA corpus and 3.6m words of random samples from the COHA corpus are available to download now:
COCA samples: http://corpus.byu.edu/cocatext/samples/text.zip
COHA samples: http://corpus.byu.edu/cohatext/samples/text.zip
The full text versions of COCA and COHA can also be purchased at $245 each (or $375 for both) for a single user licence: http://corpus.byu.edu/full-text/purchase.asp
COCA samples: http://corpus.byu.edu/cocatext/samples/text.zip
COHA samples: http://corpus.byu.edu/cohatext/samples/text.zip
The full text versions of COCA and COHA can also be purchased at $245 each (or $375 for both) for a single user licence: http://corpus.byu.edu/full-text/purchase.asp