I played one once before and it worked like this.
Everyone first bought in for the same amount.
Everyone got 5000 to start with, If at any stage in the first 120 minutes you went below 2500 in chips you could get a top up for 5000 but only one. You could NOT do this mid hand only between hands - same as any rebuy rule.
At the end of the 90 minutes everybody who hadn't rebought got a 5000 chip regardless of their stack.
That was it -
