Hey maca1214,
Welcome to the forum indeed!
Whereas the article Alan mentioned does suggest 100 buy-ins (BI), 100 BI is not nearly enough, especially when playing large field MTTs on PokerStars, for example. In such cases, you will want to think more like 200-300 BI or even more, dependent on how large the fields are, as well as other things. For example, you probably won't need 400 BI for the 180 man tournaments on PokerStars, but for playing the standard large field MTTs, 400 BI is definitely not unreasonable!
Also you will find that most tournament players work with average BI instead, allowing them to play a few higher BI tournaments every now and then, as long as they play some lower BI tournaments as well.
If you want to start playing tournaments with a very small bankroll, then you are probably best off starting with the micro stakes MT SNGs. You can buy into these for as little as $0.25 (possibly even less?), and won't require a 400 BI BRM, that's for sure. At the same time, they are great for starting to build a bankroll and getting a good idea of how to play MTTs. These also have much less variance than the larger MTTs, which also helps a lot for your mindset, especially if you're a beginning player.
I'm sure Asaban will be here shortly to give you even more info on this (:megusta: ). But trust me, 100 BI will not be enough for the big MTTs!
Kind regards,
Tino