$300/year but can you imagine designing for business with it and when you’re thinking about selling your company you list your assets and you can not list any of your designs because the only way anyone else can open and use them is with a perpetual $300/yr payment. We’re not talking about creating any new designs, just to view and edit you have to pay for that right yearly.
Maybe there is a free viewer which runs on all platforms and will run on all platforms in the future but I’ve not heard of it yet.