Looking for a cheaper portable LED light for on location filming or photography well this is the $20 light. First you will need the items in the photo below. The poster board was $2.50 the wire was like $6.00 and the LED light strip was like $8.00 on amazon free shipping. Now I had all the tools if you have to buy the tools then this cost you a little more but not much. If you do have to buy the tools and battery holder then it might cost around $35.00
Decide what size you want your light to be and mark the poster board with your favorite marking tool. I am going to base this off the size I made my light so I made my board 14"x 11-1/2" . Then cut out the poster board with a razor knife be careful not to cut your self. After you have the board cut out measure 1" make a line parallel with the 14" side then space you lines 5/8" apart. The draw lines parallel with the 12" side 1" inch from that side on both sides. These lines are to keep the LED strip lights straight.
Step 2: Cut LED Strips
The LED strip lights have cut marks on them with a picture of a pair of scissors be careful to cut as center of that mark as you can cause it will determine how much area you have to solder too. So cut the strips at 12". With the roll of lights I purchased I got 16 strips.
Step 3: Trim The Gel Off
The LED strip I have are water proof so thy have a gel cover you have to get this off the term points to solider. I used a razor blade to cut into it but not all the way just go about half way then peel it off this can be a little cumbersome but it doesn't take long.