Inverter

Hello everyone,i'm designing an inverter of o/p about 150watts 240v at 50hz from 12v car battery. I have a circuit diagram that incorporates a 555 timer a pnp & npn (TPI) but i have seen several critics on this circuit on other threads. Could someone help me on an alternative more efficient circuit

Once again it'll be cheaper to buy than build.

Buying is the easier option but i wanna have the joy of developing one myself. Secondly these cheap china models are not worth it. They may break down any time