I think where you save money with the lean to's is a typical 40 or so wide pole barn with an additional 12-20 lean to on the side vs a 50-80' wide clearspan truss, those big trusses get $$$. A 16 wide truss with 8 on each side is too much futzing around to be worth the money you save vs 32' clearspan trusses, that's just for the enclosed space, not even considering the flexibility of an open building. You'll save very little in heat between the two designs, the outside envelope area is the difference (assuming same insulation) and that's only the difference in end walls, your height and width remain the same. The added complexity for the side wall above the roof, the wall to roof transition, and insulation and air sealing challenges are not worth it.
If we're talking about a shop with a heated slab, finished interior etc, the difference to get 36' trusses is peanuts. Don't be penny wise and pound foolish.