i was working with JY-MCU quite a lot. It's cheap enough and since i am usually working only with slave devices, it's a good choice (IMHO).
I am looking for cheap alternative, which would support bluetooth V4.0, but they are a lot more expensive. I found two modules but both without socket and power regulator (interface board).
Does anybody know for V4.0 module with interface board in (approximately) price range of JY-MCU?
I think in this case you need a level converter between 5 and 3.3V. I have tried some thing like this to interface a sim card directly to the 5V microcontroller, at that time i used a simple level converter using a not gate 74HC04 and given 3.3V to this inverter IC, so 5V from the pic will be converted to 3.3V. You can also use a transistor drive circuit i have attached. I think it should work.