ill get in first and say what everyone else will say...do you have a decent grinder? *as you will notice on reviewing this site, the grinder is the limiting factor and you need to spend at least a couple of hundred dollars on one (preferably more). *If your budget is 400 all up then youre quite limited. *Id look at spending all 400 on the grinder and then look to invest in a second hand machine.
regarding the machine...it will depend in part upon what kind of drinks and how many you need to do at one time. *
if you provide these details regarding usage, grinder and max budget, youll get some more useful advice *;)