For those who don't trade "EXPENSIVE" stocks:

Current share price:

$AMZN $2640 (expensive stock)
$ZNGA $9.33 (CHEAP stock)

Both recently ran 8-10%

2 shares AMZN at 2400 cost $4800 = $480 gain

550 shares ZNGA at 8.75 cost $4800 = $319 gain.

2 shares can be better than 500.