You won't get much for this amount for a computerized machine these days. If you had purchased a 'good' machine to start you would not be looking for a fourth machine at this time. All the money spent on three machines could be saved to purchase one 'good' machine. Sewing machines are like everything else we buy, appliances, furniture.
Its better to buy good quality and have the product last for years than buy cheap and have to replace it every several years. You end up spending more in the long run. Save your money until you can buy a good quality machine, even if its a used machine it will still last, and perform better than a cheap $200 machine.