Well,some time you could rehab mall in Hawally, just in Thursday and Friday.
use the locator on the wizards website.
You can find tournaments for magic cards at Magic The gathering in San Francisco,Ca or at 2154 university ave. in Berkeley,Ca.
In France? eBay, Troll and Toad, ABU Games, and other online stores have foreign cards.
Major Retailers carry them. If you are looking to buy single cards usually comic stores are a worthy bet.
Your local cards store should have details of tournaments. you may also find information with regards to tournaments at Wizards of the Coast webpage
Assuming you dont care about format restrictions and wants the best cards: Argivian Find, Rofellos's Gift, Regrowth, Eternal Witness.
Thee are a number of websites that you can go to and input a decklist of cards then order them online.Starcitygamescoolstuffincchannelfireballallmagiccards
There are hundreds of places online that you can find the Deckbuilders toolkit. Coolstuffinc, Channel-fireball, ebay, trollandtoad, starcitygames. Any card store that stocks magic cards should have them or be able to order you one.
The best place to get cards is at a local 'shop'. Hobby shops which sell Dungeons and Dragons, Warhammer, or comics usually sell Magic The Gathering cards (and generally cheaper than larger retailers) in booster packs (15 to 16 cards) and have singles for sale. You can also often find booster packs, as well as, pre-constructed 60 card decks at Wal-Mart and Target.
go to wizards of the cost.com
www.BlackBorder.com
Magic is played on many, many college campuses. To find out if there is an organization on your local campus one should contact the activities office. Since magic is so popular with college students, if your campus doesn't have a magic the gathering club, you should consider creating your own.
This site is useful for checking out new cards before their initial release (i.e. Worldwake): http://www.gatheringmagic.com/ If you're looking for information on cards that have been archived/already released I would go here: http://gatherer.wizards.com/Pages/Default.aspx (this site has a really nice intuitive interface, and it's typically where I go if I want to gathering ideas for deck construction). Hope that helps!!! :)