I think the diamonds question has been answered.If you want cheaper stocks to trade with no spread then there are always stocks like Intel.Accounts can be opened with 4/1 margin, minimum $2000,and you can do as many trades as you want every day.
With these type of accounts you can also trade NTES,SOHU,SINA the chinese internet stocks which at the moment are just red hot and a real day traders delight.4,200% rise in under 12 months and still going!
Attached is print of Intel showing how tight the spread is.