Well the answer is it depends - 8 teams make the playoffs and receive a portion of the pot for doing so (obviously its a small portion - the teams that go the farthest get the most). Is your $60M team going to beat a $100M team (assuming its $100M worth of good contracts and not lousy ones) - probably not week in and week out but it can happen. In fact the league I currently play in, the team who is overwhelmingly the most talented team by far in the league has only one the championship once in the past few seasons.
Things happen - players get injured, the playoffs are in the home stretch of the regular season so sometimes stars are playing less minutes - starting right off the bat all the teams should be on fairly equal footing because we're drafting teams. Where it goes from there is really up to how well people manage their teams.
The weekly lineups are 12 man lineups in a 16 team league - thats 192 players and there are only 150 NBA starters so having LeBron or any one star doesn't necessarily mean anything. If you fill your lineup with 16 Bruce Bowen's you'll suck and won't win anything but you could also look for more of the semi-stars and blossoming players and maybe have just one mega star.
You can be competitive for the $30-$40 fee range if you're disciplined. If you're willing to move that semi-star once he gets to be a little too expensive for your tastes, if you're willing to scour the league for inexpensive yet useful players and play young players (at least those starting with the incoming NBA rookie class and beyond since they will all be on cheap "rookie contracts") then sure, you can do it. Can you win the championship? That's not a guarantee even if you spend more than everyone else - but you certainly can be in the mix of the playoff race.
Generally the guys who spend like crazy (and that's usually a minority in the league) do have good teams, don't get me wrong. They probably will make the playoffs but aren't guaranteed to win it all. You have to think like a small market team though if you want to limit yourself to the very bottom of spending. You can't expect to have a team full of NBA stars for that but there will never be a shortage of people who will trade for stars either. It takes discipline, sometimes even just letting a player go for little or nothing if you've decided that's all you're going to spend but a well managed team at the cap can be just as good or better than a poorly managed team who spent alot. Like I said though, if one team somehow accumulates LeBron, Paul, Wade etc and that's what is making up their $100M roster then everyone's pretty much screwed regardless of what you spend
