I've received the following announcement of a reasonably priced facsimile of Erasmus' 1522 GNT:
Bibles.org.uk has published the facsimile of Erasmus' third printed edition of Greek New Testament, originally published in 1522. Colophon to the Apocalypse contains the date 1522 but the Introduction says 1518. It contains both the Greek and the Latin (Erasmus' own translation) texts in parallel columns.
This is the first printed edition of Greek NT to contain the Comma Johanneum (I John 5:7-8), howbeit in a rather unusual form.
This edition was used by Tyndale for the first English New Testament (1526), by Stephanus as a base for his 1550 edition and by the translators of Geneva Bible and King James Version.
The direct link for ordering this edition is here.