"What kind of charts
do I need for TIKI Navionics Gold,
and where can I buy them?"

You need Navionics+/Gold or Platinum+ charts
on a SD/MicroSD or Compact Flash card.

You cannot use downloadable Navionics charts for iPhone, iPad or Android smart phones or tablets. You have to use the cards made for chart plotters.

But unlike hardware chart plotters, TIKI only needs the card one time for copying the charts to the hard drive of a computer, and you can do this on 3 computers.

If you have a chart plotter for Navionics, this means that you can run TIKI and your chart plotter simultaneously with just one card.

Where can you buy Navionics card?

Navionics has distributors and dealers in most countries. Any shop that sells chart plotters from Raymarine, Furuno, Lowrance, Eagle, GeoNav, NorthStar, Simrad or Humminbird also sells Navionics charts.

You can also buy Navionics cards from several webshops like:
US: Landfall Navigation
UK: Yachting Software
France: Nauticom

Should you buy Navionics+ /Gold or Platinum+ cards?

The 2D charts for navigation are the same in Navionics+ /Gold cards and Platinum+ cards. But Platinum+ has some additional features like 3D charts, satellite overlay etc.
If you have a chart plotter that can use Platinum+, you may consider Platinum, but Navionics+ /Gold charts cover larger areas and cost less.
TIKI can read both types of cards, but does not use all Platinum features - so if charts for TIKI is your first priority I would definetely recommend Navionics+ /Gold charts.