Approx cost for glass roof

[henry]

I have a 10*10 courtyard space and i need to put some kind of roof. So kindly suggest which option best

1) as pergola or equivalent are very costly, if i Put toughened glass with supporting rods, how much it may cost ?

2) can we put upvc frame and toughened glass (just like window frames/glass). How much will this option cost

3) If i just put rods and leave it open but if it rains its a problem, so if there are any other type of doing this.

Basically idea is I want visibility so dont want any opaque roofs but would like glass.

Appreciate your ideas and approx cost.