Looking for Advice for Ticket Buying

So I don't go to many games usually just buy on Stubhub or Ticketmaster. I actually have tickets to go to the game against the Magic next Wednesday.

My wife's cousin is from Florida, and is a Heat fan so i was looking for tickets to the game on April 10th, and anything I have found is double to triple the price of the Magic game. I will pay it if I have to but i was hoping anyone who went to more games maybe had some advice on when to buy tickets/a specific site to buy from or I was even thinking try the box office when I go to the game next week.

Thank you in advance for any and all advice!

Lets Go Nets!!!