Discuss… I dont know too much about these.
These cards were awarded to participants in the Tropical Mega Battle. For each battle won within a 15 minute time period, an envelope containing one of three phone cards was awarded. Since it was up to chance which was was received, obtaining a full set was extremely difficult.
The cards:
Articuno Phone Card by Pokemon Card Collector, on Flickr
Zapdos Phone Card by Pokemon Card Collector, on Flickr
Moltres Phone Card by Pokemon Card Collector, on Flickr
The Envelope:
Phone Card Envelopes by Pokemon Card Collector, on Flickr
They are actual working phone cards that can be used to place domestic and international calls from Japan. Each card has 50 units of talk time if I can remember correctly. The back side of the cards are grey and …well look like a phone card instead of having the normal Japanese backs. Contrary to popular belief the cards are not longer, they are the same height as a normal card but are slimmer to keep the correct proportions. Supposedly, only 50 or less were printed. I have not seen that many at all so they are quite rare.
That’s all I got 
Where did u find yours?
I got them about a year ago from a collector. He had them on ebay but we made a private deal. I think I only know one other complete set.
Do you mean my set? If not, you now know another one 
Yes sir! I was refer to yours Do you happen to know anyone else with all three?
Nope, I only know the one I sold my doubles of zapdos and moltres He’s only missing the articuno for a complete set
What is the price range of these?
Around 1500 or so for the set. 300 to 500 per card.