I usually buy tickets within 12 hours of game time. Tick Pick is my go to. It almost always has the cheapest available tickets including fees. Got baseline floor seats against the clippers last night for $200

You can get vip section seats that include Qatar club access for less than $500-$600 depending on who the team is playing. There were a few available last night against the clippers, which are considered a marquee match up, for $450. So against a lower tier team you can DEFINITELY get vip seats well within your budget