Hi Prawn,
Tourist Cards .... the cost of the tourist card upon arrival at airport is $10 USD per person, BUT, it is very easy to purchase it online prior to travel, and saves a lot of hassle upon arrival at airport. This is the link to purchase online https:www.dgii.gov/Tturistaweb/
Currency .... we took USD with us which were accepted wherever we went.
Tipping .... we usually tip as we go along but that's just our preference. Can't see any problem with tipping at the end of stay though.
Immigration card ..... you will required to fill in a blue Immigration Card which you hand in upon arrival at the airport. This will be given to you once you have boarded your outbound flight.
Hope the above is of some help:-)
Regards,
Pat