You can try out Gavagai Explorer for free - just create a new account at the sign-up page.
While in the trial, you can try every aspect of Explorer, including creating projects and analyzing verbatims. At the end of the trial the accumulated charges will be wiped from the account and your balance will be set to zero.
To continue using the account you must then either enter your payment details or contact us at firstname.lastname@example.org if you would like to be invoiced instead.
If you do continue, you will not be charged unless you use the Explorer; there is no monthly charge for just having the account.
When you do use the Explorer we charge according to How is usage charged for Explorer?