You may find a running step through for 400.00 though most good shape ones are on cragslist for like 900.00-1,100 now thanks to flippers who don't care about the moped community who just flip and flip adding hundred of dollars each time until the bike is selling for a grand. And that's just for a common bike like a tomos.
For a turn key good running top tank puch bike you will pay much more 400.00
Past two that sold went for 1,3-1,500.00 .
I got this ^ it needs nothing but a rider.
Eventually you want a top tank everybody does it seems