I have found if you really want to make a decent return on investment with MH you have to be in for the long haul, buy the dolls then sit on them for a few months. With the constant refresh in cases and limited availability a doll that cost you $24 could net you $60 or make good trade fodder for exclusives that you might miss out on. Worst comes to worst you get retail cost for them so you lose nothing, you can help others out (I do this all the time) at cost.
That is not being a scalper though, that is being business smart and knowing how to invest in your collection instead of just hemorrhaging money buying dolls. But sadly I know people like myself are probably in the minority, especially hearing stories like Bonehead's with people buying an entire store out of dolls.