How can I make a DIY sheer vertical window shade?

How about a different approach? Have you thought about old fashioned roller shades and sheer curtains? This will bring the cost down to under $100.00 each window. Really under $50.00

The window is over 10 ft wide and only 45” high with 2 operable flanking sliding windows to the center fixed window, the roller shades are already existing and she is not able to get any light or air in with out a privacy issue, she also is 75yrs young and can not lift her right arm over her shoulders...which is why I thought the vertical blind would be a better option as it is maneuvered with a manual wand that is 18” long ...right about her chest hieght.

I have four 8 foot wide sliders that face West, so I know what you mean about the expense. And because our home is open concept my window coverings have to match each other. The "trick" is more in the hardware than the fabric. If the curtain rod is round you can buy rings with clips. If you have a traverse rod you can buy clips that ride in the track. Gather your fabric panels from places like Big Lots, Walmart, or Target. Each plain panel is about $5 and is about 40 inches wide. If you sew you can attach them to each other to create a large panel or two. Then you just pinch a pleat in the top and clip it to the hardware. Start in the center of your panel for the first pleat, then make the next two pleats on the left and right centers of that first pleat. Continue dividing your panel like that until you have all the fabric hanging from the clips in pleats. Adjust your pleats according to how full you want the curtain and the amount of privacy needed. If you need fabric to cover very tall windows (longer than 84" or 96") you can do the same thing with curtain scarves. They are finished on the ends, but with very shallow hems so most likely they will need to be hemmed on tbe bottom.

If you want to hang these behind verticle blinds you may need to get creative with your rod placement so that it allows the blind mechanism to work.

You should try window film, it comes in many shades and designs. It will block out the sun and give privacy. Easy to do yourself. You can get it at most bigbox home stores.

• Get WINDOW FILM -- HomeDepot-- GILA brand -- reflects 98% solar energy BACK toward the sun! Dropped the glass surface temp on my west facing windows by 15 degrees (Southern California). It is totally amazing at the difference. It's a project to install-- mix up your own wetting solution: you will need a large spray bottle filled with water, 3 -5 drops of dish washing soap (I use Ivory, others have used BABY SHAMPOO!), use a 8-10" professional window washer squeege. Wet glass, peel off backing paper, wet back side, put on glass, position by sliding around with light hand pressure, spray/wet front side, gently squeege start at top center gradually work OUTWARD and downward ... You can reposition while wet, firmly squeege soapy water to smooth film and set in final position. The plastic scraper blade & wetting solution kit are both TOTALLY USELESS! Making your own solution is cheaper, more reliable, and much more efficient. Installing the first panel of film is a learning situation-- after that-- you are an EXPERT!!! Start with a smaller easily accessible window to "practice" on! If tiny wrinkles appear, re-wet both sides with spray and smooth them out. By trial and error, I learned by doing, wetting/positioning/squeege a bit at a time gradually working my way down the window surface. The film is removable, and can be re-used at another location. Just gently peel off glass, carefully roll up, and relocate. I cut my film panels a bit over sized, then trimmed sides and bottom with an Xacto knife to remove the excess. Follow the shape/edge of the window frame. The top edge/end of film & window frame are usually "true" -- that is a good straight edge starting reference point. When you want to "clean" the windows, use a damp soft CLOTH (NO paper towels!!! -- could "scratch" the film)to wash, + a soft cloth to dry. Many videos on YouTube to watch to learn this also ... It is very helpful if 2 people are invovled with installation. I did it all alone, it was a tad cumbersome, but manageable!!! Hope this helps & GOOD LUCK!! You will enjoy the reduced heat/indoor temperature after film installation! It does make a HUGE difference.
• 
  

I discovered a wonderful site for purchasing window coverings and ordered cordless 2-inch horizontal blinds from them. Love, love, love the blinds and the price as well. You might see if they have a solution to your problem. Check them out. Here's a link: https://www.selectblinds.com/search.html?Q=vertical+blinds.

I would get the heat reflective window film that comes in 5 basic colors: silver, smoke, gold, bronze.... https://www.amazon.com/s?k=heat+reflective+window+film&ref=nb_sb_noss_1