Thanks for the instructions! Here's my version. I haven't built much of anything before, but I needed it in my basement to handle kids' stuff. My version is 18 feet long. I combined a 12-foot and 6-foot 2x4 to get that length, which meant less cutting, which I had done at Lowe's (for free). I used the 6-foot 2x4s throughout the shelf to ensure it was strong (in other words, I didn't want a 12-foot "section" and a weaker 6-foot "section" added on).
I was able to get everything in my car but the ride home was slow. I also had to use my egress window to get the 12-foot boards in the basement.
Total cost for me was about $170 including a couple boxes of screws and wood glue. I could've easily spent double the cost on store-bought shelving. Thanks for the plans!