I have just found this post on AndersRuff and this is exactly what I have been wanting to know for a while... : How to display those pops which are so trendy ???
I have used cardboard boxes filled with polystyrene in the past but they were bulky. I guess I was always afraid foam would not hold the weight of the pops. But apparently it does.
They have used styrofoam block for the base. You then cover with paper to match your party theme.
Read the complete tutorial, advice and the party details here.