This is extremely low poly but you can adjust it depending on what you want..

Start with cilinder






Just use polygon pipe, you can adjust its roundness in channel box by changing 'subdivision axis'.. then right click on the mesh > choose faces > delete the faces on the bottom and inside of the pipe.. The rest you do with extruding edges(4). Left click on mesh > select edges. Double clik on an edge to select the edges all the way around. Then click extrude and either 'w' or 'r' depending if you want to move the edge along the axis or scale it up or down. Click 'q' (exit tool), then 'g' (re-choose last tool) and keep going..