Until recently, I used a 10ft x 20ft popup tent for getting softer light on sunny days. Bought for $1200, the tent lasted five years and was well worth the expense and the effort required to set it up. A couple of weeks ago, the tent was damaged by a storm and repairing it would take a while. That prompted me to try a more portable solution than the 90-pound pop-up.
In movie-making, the standard solution is silk stretched on a frame and raised on two stands. Due to the heavy-duty stands and sandbags required to keep it in place, the entire set of equipment is actually heavier than the tent, but individual components are much lighter and easier to move.
I just priced the 12ft x 12ft kit at B&H: $1520 with shipping. All that for one light modifier. If you ever wondered why professional photography is expensive, this is one of the reasons.