Interspire is no longer available for sale:
Interspire Email Marketer has stopped accepting new sales. If you are an existing client and need to upgrade the number of users or install it on a new domain you can email firstname.lastname@example.org to receive a free upgrade or free domain transfer.
If you have an active support contract it will expire on the 24th of May 2019. After this point Interspire Email Marketer will no longer be supported.