Janet has 10 action figures and sells 6 so she has 10 - 6 = <<10-6=4>>4 action figures left.
She then buys four more so she now has 4 + 4 = <<4+4=8>>8 action figures.
Her brother gives her his collection which is 2 * 8 = <<2*8=16>>16 action figures.
Now in total, she has 8 + 16 = <<8+16=24>>24 action figures.
#### 24