Establish Fake-Money play first
"Wait for your last trade to process before trading this" So you can only make 1 bet at a time??
My advice is to give out some REP or some fake-coins to test the market first, similar to online casinos letting you play with fake money, or sorta like how Zynga did their poker, with fake money but the results are real (you can lose or make fake money based on how you play). Then your initial users get an idea how everything works, BEFORE committing to funding the account. This method in business ALWAYS works to generate new paying accounts.