Hi,
I have 3 presales question:
1) do language of jevents change authomatically when I change in front end joomla language (using the Joomla Standard Plugin Language switcher, that is the standard flags in joomla multilanguage sites)?
As long as you have the joomla language filter enabled the JEvents interface will change language for you. We also support translation of events and layouts.
2) I have a nice template in my website abcmaremma.it, can I use jevents in my template? My tamplate is a Joomla Bamboo Template, that use Joomla Zen Tools for slideshow, menus etc.
I can ask also to Joomla Bamboo forum, but I think it's better asking here.
Should work fine - at worst you may need some CSS overrides if there are minor style clashes
3) can I set some categories of events for free, and set in the same site for other kind of events, a paypal payment?
RSVP Pro (our gold member addon) allows you to charge attendees for events with ticketing, custom fields, reminders and invitations built in.
I would suggest you try it and if it doesn't do what you want then you can request a refund.