auuri

Collectible Card games have always been fun for me.
I've played quite a few...

Pokmeon, Magic: The Gathering, L5R, WoW TCG and Yu-Gi-Oh are the main ones I can recall.  I've always wanted to get into playing them online, and since, I recently came across www.setokaiba.com/KCVDS/ . A free Yu-Gi-Oh online one...
YuGiOh's one of the simpler ones, and often jeered at, but...
For a "Free Deck " System, this is probably one of the easier ones I've been able to get into.

Since, unless you kept up with ALL the cards or don't mind spend hours upon hours reading the effect of every single card and trying to come up with the strongest synergies... Your deck will probably suck pretty hard.
Granted, it still applies to this game, but... Since I'm both more familiar with it back from playing in middle school and the cards tend to be really simple, it's easier for me (though I'm sure my decks still suck).

For a short time I played the official one... At least the first couple of "Free Duels" you're allowed. What I liked about that one was the deck limiting (which also applied to which lobby you could be in, so more powerful decks often didn't fight against lower level). You started out with a Starter deck, then as you won/played duels you'd get booster packs or points to buy new cards with. This allowed me to play without the hours of reading and comparing... And made it more fun for me...
But I didn't want to play bad enough to pay...

 

Anyone know of any other Free online TCG?
Deck limiting is optional, but preferred, since I don't know all the cards to any of them.