If its cheap
, generally it's cheap...ie no good..
If you are serious you should buy a serious navigation
suite and buy the real charts.
Paper charts also are essential..AND you should know, if you don't already, that many of the Pacific charts are out by MILES
'cos since all these island groups became independent they have to take up responsibility for updating the charts...and they don't..they have MUCH bigger issues to deal with than a few sailors cruising around their islands.
SO...even if you buy electronic charts for the Pacific they will be ot 'cos they're based on tge paper charts which haven't been updated.
There's a chart for Va'vau in Tonga
which I think goes back to 1867 and its not only out lat/lon but North isn't North !!