RE: is this a good RTF plane to buy..???
It depends on your point of view, the web page gives a price of $100. If you really paid only $20 for it, then you haven't wasted much money on it.
This plane looks typical of a lot of the cheap electric planes available. It might fly ok, on a calm day in the local park but it'll be nothing like a 'proper' 3-4 channel electric or engine plane.....