The refills cost just over $10 for the two from the dealer. Installation time was about 30 minutes. It's probably posssible to do this without removing the blade arm, but I think it would be a major hassle trying to get the refills back onto the arm. It is still awkward doing this job, but if I can do it, anybody can. The hardest part is pulling down the end of the rubber arm cover to allow the removal of the old blade. If you have arthritic fingers, have someone else do this job. Although I had no mishaps, it might be a good idea to put a cover over the hood to prevent scratches in case the arm gets dropped during the removal process.
Don't know if I'm comparing apples-oranges, but I had my 23 yr old grandson change mine. I bought my refills from the Toyota dealer as the local auto parts chain carried only blades. By the way, I'm driving a Prius.
Like you, my g-son was surprised at the amount of effort it took to get the blasted things out. Instructions on the packaging were useless so he had to go to the internet for instructions.