User ID's, conditional fields and a few other q's.

Can Gravity Forms generate a unique ID code for each user that signs up, and display this to them on their confirmation screen/email? Worst case I can write a script to generate the code, but we'd like it displayed to the user so that they can refer to it for support and payment issues.

The entry ID is unique across all form entries. Is that unique enough, or do you need it to be more complex than that?

Can we include a simple value in the database that won't be displayed/available to the user? We'd like to indicate if a user paying through bank transfer has paid or not.

You can add an admin only field which is blank, and your adminstrator can change that status when payment arrives. The admin only fields are not visible to users, just logged in administrators, in the form entries (not in the form which is displayed to the visitor.)

We'll be using Gravity Forms to register for an event. With conditional fields, can I set it so that, for example, if a user selects that 3 people will attend, 3 sets of personal information field sets appear?

Field sets are not a feature of Gravity Forms. However, there are a couple ways to handle this. We have a list type field, and you can determine how many rows (attendees) to allow, based on the value of a drop down (the number of attendees.) Please see this: http://gravitywiz.com/2012/06/03/set-number-of-list-field-rows-by-field-value/

However, that might not be what you're looking for. You may want to have a complete address block for each attendee. In that case, you can add multiple attendee blocks to the form (some finite number) and then allow the visitor to select from a drop down how many attendees. Then, use conditional logic to show the correct number of attendee blocks based on the number of attendees chosen.

If I want to calculate costs, can I do that across a multi-page form, and can a running total be listed on each page? Only some of the fields we'll be using will be used for final price calculation. Also, can we display a summary of costs/total on the last page as a confirmation, or something similar?

Yes, calculations are built in, and you can display the running total on each page.

Can users elect to sign up to a newsletter during signup using existing Wordpress newsletter plugins, or will listed add-ons like MailChimp be the only option there?

Integrating with other WordPress plugins is possible. We would have to see which plugin you're trying to integrate, then after the form is submitted, if the opt in check box was checked, mark them as a subscriber in your other plugin. How it's done will depend on the plugin you're using. If it's all based on your site, it should be fairly easy. If it's off site, we can handle that too, by using the available gform_after_submission hook to send the data for a subscription.

Let us know if you have any other questions we can answer before you make you purchase. Thanks.