Most good players make more money from playing the game then they do from rakeback. I'd rather play at the highest level that I'm rolled for and can beat well.
Find the level that you are rolled for and where:
Profit from Playing + Profit from Rakeback > the same equation at all other levels
Also even if you want to use 20BI's as your necessary bankroll which isn't necessarily true (your bankroll requirement is a function of your winrate, your standard deviation, and your risk tolerance which can be expressed as a formula and your bankroll requirement can be calculated) .... but anyway even if you want to use the 20BI's as your bankroll necessity buying in for $50 in a .25/.5 table is not the same as buying in for $50 at a $1/$2 table. You would still need a larger bankroll requirement for the $1/$2 even though you are only buying in for $50. You will experience more variance at the $1/$2 tables.
Think about this. Even the best shortstackers (20 to 30 BB players) in the world don't have winrates that exceed 2PTBB/100hands by much (and most shortstackers do not exceed 2PTBB/100hands) while good full stacked players can get over 4PTBB/100hands.
Since as I said earlier bankroll requirements are a function of several factors including winrate the lower the winrate the larger a bankroll you will need because the more variance you will experience. If the world's best shortstackers can't maintain a winrate as high as good full stack players I think that if you buy-in to a $200 table with 25BB's your winrate will be lower than your winrate buying in for 100BB's at a $50 table and thus you will need a larger bankroll.
(That was all assuming a decent winning player. I would actually hazard a guess (no offense intended) that your winrate may be higher buying in for $50 at a 200NL table rather than buying in for $200. This is because I am assuming from your question and your post count and you being in the beginner's forum that you are not very good at poker. I assume you would lose at 200NL .... however, if you only have $50 you would not be playing so many turns and rivers and losing big bets as you would be if you bought in with $200 so you may actually need a smaller role to buy-in for $50 than you would if you bought in with $200. Of course if you're a losing player all of that really is just a misnomer since losing players do not need bankrolls at all since they will just steadily lose at some pace depending on how bad they are anyway. So losing players really need a budget, not a bankroll.
Also as you move up the levels tend to get harder to beat as there are more good players and less bad players. This also causes winrates to decrease and causes bankroll requirements to increase. If Ivey played 5NL he would need a much smaller roll (smallerness is much understated) than he would need to play 100,000NL.
If you plan to get into online poker cash games I suggest you start somewhere in the micro stakes and also try this:
Read all the stickies in the micro stakes forum.
Read all the stickies in the small stakes forum
Read this (3rd post down):
http://forumserver.twoplustwo.com/32...thread-340027/
Look into getting either Poker Tracker or Holdem Manager
Download Pokerstove (it's free at
www.pokerstove.com)
Post hands in the relevant forum (probably microstakes) and ask questions after people respond if you don't understand something or whatever (You can post hands in this forum also if you want.)
Read the hands that other people post and read the comments others make and try to make your own comments and then read the comments people make about your comments. Ask questions as needed.
Maybe read some books like "No Limit Holdem: Theory and Practice". Also some I haven't read that gets mentioned "Harrington on Cash" and "Professional No Limit Holdem".
You can look into joining training site(s).
If at some point you decide you want to you can look into hiring a coach.
If you're going to join a site where rakeback is available make sure you signup in the manner you need to in order to get rakeback.
If you're signing up at a site that offers a deposit bonus deposit enough to take full advantage of the bonus. (If you can't deposit that much yet then play at a different site until you can deposit enough and then switch if the bonus is still worth it to do so.)
Good Luck
