Hi!
I was checking on ebay the promo set of Gym Badges and I have come across a stamp that I hadn’t seen yet. Apparently, it is the stamp of the Pokemon League.
Does anyone know what’s the Pokemon League? In Bulbapedia says that it is a contest held weekly. Then, if it is weekly, is it really common? And how does it affect the value of a card? What version would be better: a card with the stamp of the Pokemon League or the same card without that stamp?
Thanks for your help ^^
The Gym Badge promos XY203-210 all come with the pokemon league stamp. They are awarded at local leagues held all of the country(s). If you could find an english copy without the stamp, you would be on to something rare. It’s as common as how many people got them for their leagues, so an unkown amount. Will probably be highly sought after, so may be good to get them now.
@alicia Are these the ones you’re referring to? www.ebay.com/itm/Pokemon-League-Promo-Set-x4-RARE-Pack-Fresh-/182513216716?hash=item2a7ea2accc:g:wNEAAOSwuLZY2HOu
Interesting… @quuador you got that Pikachu already?
@alicia its the same stamp in the Mew 1st place -4th place. Check those out too 
Pokemon Leagues are weekly play groups held by certified Pokémon Professors. They are held all around the world! Some are in libraries, some in card shops, and some in restaurants! Leagues are the foundation of the Pokémon Organized Play system.
While it is held weekly, promos are not necessarily earned every week. For most of the history of Pokémon Leagues, promos have been earned by completing a small booklet that requires so many matches, trades, or other interactions before a promo is earned. Here is a photo example of one from back when they gave away badge pins.
Is it common? Well, that’s relative! There are far more players than leagues. Leagues also often involve people who aren’t connected to the online community and marketplaces. So yes, it is common compared to a specific tournament promo, but it’s much rarer than a blister promo or a target promo, for example.
The value of the cards is never super high. That said, Pokémon started printing playable trainers and very collectable cards (Pikachu and Gym Badge Promo Cards) a couple years ago. The value on these has been much higher because they are worth getting excited about. So the value is kept relatively low (never seen a promo over $20) by their availability, but individual card desirability can still bring the value of the cards up to a respectable value.
The league promo version of a card is almost always slightly more valuable than its unstamped equivalent. This is because there will never be a more common card than one that comes from a pack. This goes for every single pack card ever printed. 1st edition cards have tens of thousands of copies. Hyper rares have millions of copies. But promo are affixed to a certain time and place. This gives them uniqueness and scarcity that is not true of standard release cards. Because of this, there is a value bump.
If you have any more questions, ask away! 
@funmonkey54 Great write up!
And @jjnoriega the Mews League stamp is a little different. Says “League Challenge” as they are an award for placement instead of just “Pokemon League”
Learn something every day!! Thanks for pointing these out, would’ve never noticed!
Yep. Bought it right when it was released.
Greetz,
Quuador
Yes! That’s the stamp!
So is it better without the stamp? 
Wow!!! Such a complete answer!!! Thank you very much!!! Crystal clear ^^
They do not exist without the stamp in English.
Off topic. which japanese promo card version of that same pikachu art work come from?
Oooooh, I get it know haha Thanks! ^^
There are two Japanese versions of that card. A glossy and a non-glossy. The glossy is from the Vending Series 00 and the other from a theme Deck. Here on Bulbapedia is more information about its releases bulbapedia.bulbagarden.net/wiki/Pikachu_(Wizards_Promo_4)#Release_information
Greetz,
Quuador