I'm putting together a shopping list and moving my station to another part of my house. I don't really wanna paint the walls so I looked up Mylar on lowes and I found this Pandafilm which is 10$ more for 25ft roll. Haven't ever used either so looking for other opinions.. http://m.homedepot.com/p/Viagrow-Panda-Film-25-ft-x-10-ft-Black-and-White-Poly-Film-5-5ml-VPANDA25/203478327?MERCH=RECmobileweb_pip_rr-5202985200203478327N
Another way to get a nice flat white surface without painting is foam core print mounting board. You can get 4x8 sheets at just about any picture framing supply place and it's fairly cheap for the non-archival stuff. It's light weight, but still very rigid, and you can cut it easily with a utility knife (box knife). I used to hang panels from the ceiling with string and staples to get them exactly where I needed them (it only needs to go from the bottom of the light to the bottom of the plants). With some wood glue and small wood strips (like 1" x 1"), you can build some fairly sturdy structures from it too.