Your sitting with how much?!?!

[lightfungus]

So after my trip to the casino the other day, I am beginning to think I could go make some money playing limit. Now, I saw people buying in for $40 at 3/6 games and was wondering what the correct amount to sit down with at a limit table is? We know that it is 100 the big blind is max for most NL tables, is there a guideline? Obviously its higher than $40 at a 3/6 table...