Any tips on making a manual wheelchair more comfortable?

I just bought a product called the purple cushion and it is amazing, like sitting on cool jello. Turned my miserable office chair into a comfy seat. Less than 40.00 at Sam's club but I am sure you can order online.

I would try a pillow for her back as those wheelchair backs have zero support.

This works well for my mother: Essential Medical Supply Fleece Covered Wheelchair Cushion, 18 Inches X 16 Inches X 3 Inches, available on Amazon for $18.

Rolo cushions are a good choice but very expensive. It has little pockets of air. You blow it up till you get the comfort you want. For lumbar support there are cushions for that. Moms problem was the lower back. I found a small form pillow that she placed there.

I put in cushions for wheelchair support and got these pictures

www.google.com/search?client=ms-android-samsung&source=android-home&source=hp&ei=CeWCXJS7Ccqe_QaJ25_QCg&q=cushions+for+wheelchairs+for+pressure&oq=cushions+for+wheelchairs&gs_l=mobile-gws-wiz-hp.1.1.0l2j0i22i30l3.3905.22592..26400...2.0..0.274.2820.10j14j1......0....1.......5..35i39j46i131j0i131j46i39i275j0i10.S-4rbpKWiuo

Frankly the average inexpensive wheelchair is just not designed to be used for long term seating, aside from general discomfort there is a real danger of developing pressure sores. Unfortunately any cushions and supports that are really helpful are also really expensive, unless you can find something second hand. She may be able to get some coverage for better supports, perhaps even for a better wheelchair, hopefully some of the people with better knowledge of how to go about that will be along to help.