a real roof with roof tiles and so on costs a lot of money. for that you need a proper wooden roof frame etc... the cheapest option would be a metal roof. there are also good "bleche" with anti-drip and it is not loud even when it rains. you just lay it on top of the crossbeams and screw it in place. a bracket goes around the edge and the gazebo is finished. it certainly doesn't look nearly as good as a hip roof, but it is definitely 5-6000€ cheaper. by the way, the corner pieces are expensive with the roof tiles, not the straight main pieces. if you absolutely want roof tiles, you should consider whether to choose a roof shape without these corner pieces. a roof is always the most expensive part of a carport (even the metal roof 7x6 meters costs material 1500€+). the rest is just wood and it's only the amount that matters (people tend to underestimate the amount). ps: a workshop room is by definition in many federal states not allowed to be built on the property boundary. better call the room "gartenabstellraum" or something similar (see the regulations of your federal state).