A lot of companies end up going with something similar to this, since Github Enterprise costs get a little crazy. Stash is good, but if one is looking for an even lower cost option, a lot of people recommend Gitlab now-days.
However for some, the task of self-hosting is daunting. I presume that is why some are willing to pay a lot for a hosted solution.
BTW -- It's worth noting -- BitBucket is run by Atlassian and allows unlimited free private repos. I think you must pay for teams (EDIT: Free up to 5 users, $10 per month for 10 users, etc, it's basically $1 per user per month over the initial 5 free), but just throwing that out there. It's basically their hosted Stash solution.
Plus the hidden cost of setting it up. Example: Backing up Stash - while being relatively straight-forward - comes with some amount of scripting and testing (you do test your backup, do you?).
Not saying Stash is bad (the contrary), but when evaluating cost, evaluate all cost.
Github is really attractive with all the services that integrate into it. A service at $100/mo isn't much when you consider any labor time it saves ($50-$150/hour generally)
... and Stash is really attractive with all the local plugins that integrate with it, and allow you to do things that are really hard when you're stuck with web hooks.
Local installations don't cost hours-a-month to run.
However for some, the task of self-hosting is daunting. I presume that is why some are willing to pay a lot for a hosted solution.
BTW -- It's worth noting -- BitBucket is run by Atlassian and allows unlimited free private repos. I think you must pay for teams (EDIT: Free up to 5 users, $10 per month for 10 users, etc, it's basically $1 per user per month over the initial 5 free), but just throwing that out there. It's basically their hosted Stash solution.