I use a wooden stick
A 1" X 2" rip in what ever length is screwed to the tarp through the existing grommet holes. I then screw that strip to the ceiling joists. If you want, use 2 strips, one screwed to the upper joists, and another at the bottom to help hold it's position. You can roll it up until it's the proper length.
Now way should those tarps cost $200.00. Harbor Freight has them in different grades, various sizes and different prices.
The answer to your question will only be as detailed and specific as the question is detailed and specific. Good questions also include a sketch or a photo that illustrates your issue. (:< D)
Last edited by woodnthings; 10-02-2014 at 10:20 PM.