I think it's cheap to maintain. let me know how many devs you have, how many runs you do, and how many tests (by suite) you have, and I can do you up a quote for hosting some Allure reports. can spread the up-front costs over the 3-year monthly commitment if it helps
There are several services I know who offer this for free for open source software, and I really doubt any commercial offerings of that software would charge you extra for what is basic API usage.
If you think that's easy, do it for me. I have some projects to migrate, give me the link of your service.