Solutions to your storage problems do not have to cost a fortune. Taking the time to make units just for your pole barn situation can be done, both cheaply and effectively. These pictures and details are from my own personal unit. I ran out of wall on my desk unit and solved the problem by simply putting a support under one shelf. You just have to be creative.
Lots of people have storage problems like myself. It is easy to spend a ton of money on building and buying storage units this is an ultra cheap way to do it. It also recycles stuff and keeps it out of the land fills. You can easily see I am in need of an additional unit myself and as soon as I finish moving out of my old building I will get right on it.
The picture on the right is of my new unit so you can see what it looks like without the bottles.. I rip a single sheet into 5 pieces 9 and 1/2 inches wide and 8 feet long. That gives me two sides and six shelves. Your needs may allow you to make more or less shelves. The reason I did mine this way is that it can be cut from one sheet of plywood. My bottom shelf is so high so I can set my five gallon buckets under it. You will have to figure what works for you.. The reason for my size is that four cuts equal a half inch at 1/8 inch each.
As you can see my unit consists mostly of old detergent bottles and even some kitty litter bottles. When you start planning your unit you need to measure your bottles you will be using first. Some of the larger jugs are a very tight fit on my shelves. What I really like about it is that there are enough colors out there that you can color code things. Something I have just started doing myself. You can do it in a way where you dedicate each color to a special item. Say orange for nails, red for screws, white for fasteners and hardware, blue for nuts and bolts. The nice thing about them is that you can write on them with a magic marker and know what you have in each one at a glance. Cutting them to your needs is the trick. I like to save the kitty litter ones for nails and stuff I take to job sites. Some brands of bottles have big holes that I can stick my big fat fist in and pick out what I need. I leave the top intact on these bottles. That is another reason I need another shelf unit as I made the shelve spaces to small for these bottles. At the end I will post a diagram of how you can cut all the shelf unit pieces from one piece of plywood or OSB. I prefer to use 5/8 or thicker as some of the bottles will have some weight in them. You tend to get less sag that way. One piece of 2 X 4 about 8 foot long and cut in half makes the mounting brackets and shelf supports. How you build it will depend on the type of wall you are hanging it on. This unit is hanging in a pole barn structure.
How you cut the bottle is determined by what you are wanting to put in it. I do a lot of crafts and some bottles I put lots of little pieces in. On those bottles I cut low like I did the front of the bottle on the left. Other bottles I cut the sides higher, like the back of the bottle on the left, if I need more storage. How you do it is all up to you.
My preferred way to make the units is with 8 inch sides. I figure my shelf spacing and then I use a router to cut a 1/4 inch deep groove just big enough to fit the shelf end into. (Remember this when cutting your shelve supports. There will only be 47 1/2 inches between your sides.) I then screw thru the sides and into the ends of the shelves which helps pull it all together. Then I mount 1/2 of the 2 X 4 on each side and screw it to the sides. Finally I screw thru the 2 X 4's into the perlins or the studs. Depending on the kind of wall you are working with. Depending on the height of the ceiling you can move the unit up from the floor and make extra storage for five gallon buckets or whatever else you might need to store beneath the shelf unit.
This is not the best drawing, but hopefully it will give enough info to help anyone who wants to make a unit. If you make the shelves 9 1/2 inches wide and cut all the full length cuts first it will work out so the shelves are all the same size. You will make 4 cuts which take 1/8 inch of board or 1/2 inch total for all 4 cuts. Then you can cut the 3 boards which are 9 1/2 inches wide into four foot lengths. You can cut wider shelves that will stick out a couple inches farther than the sides but it does not hurt anything unless your a neat freak. Something I have never been accused of. Rip the 2 X 4 in half and you have your mounting brackets. The spacing of the shelves is up to the builder. Note in the pictures the piece of 2 X 4 on each side vertically or horizontally under each shelf which helps give the shelves extra strength. IF you want support under all six shelves you will need a 12 foot 2 X 4 instead of an 8 foot if mounting to a stud wall. Figure 5 shows a top view of how it would be mounted to pole barn studs. Figure's 3 and 6 show how it would be mounted to a standard stud wall. Hope this helps some one create some cheap storage.