I have a recently launched software product but still have no support options, because of my resources constraints (time, money) plus other priorities (website, SEO, marketing).
So, I'm considering the next options:
What is the better option based on your expertise?
If you are not charging for support then I would definitely suggest:
1) Videos / Tutorials / Knowledge base
2) www.desk.com - it's free for one person and would be great for what you need.
I wouldn't necessarily do chat if you don't have a flexible schedule. Plus, that might not be a cost effective way of offering support. Depends what your price point of your product is and how much help people need.
But #1 & #2 would be a solid start.
Videos and tutorials do not qualify as support - though FAQ would. While you need to tell/show people how to use your product, and having a list of commonly encountered issues is useful - it doesn't help people at all when the information they are looking for isn't there.
I would suggest that initially you just have either a form on your website or at least an email address that issues can be sent to. You can use that to triage issues, and have a policy about how long it takes to respond. When you are better equipped to handle such issues, from a consumer's perspective, all you need to do is improve the response time (while behind the scenes you now track more information about the issue).
The other thing you may want to consider is having a forum where users can post questions - and other users can post answers. Without details of what your product is, and how loyal your consumer base is, it's difficult to know how effective this might be, but it is something that some businesses find to be useful in reducing the number of support questions they personally have to deal with.
Videos and tutorials are of help, but what's considered as support is something like live chat, telephone/skype consultations and support tickets.
Another option you can employ is having support forum where users can comment and solve issues each other.
Documentation and demos are aimed to be of general help but not all users have the same systems, experience and don't use your software in the same manner, so individual issues will arise certainly.
In the software industry, providing support is of the utmost importance, along with quality and relevance of the main software product, so not providing support at all shouldn't be an option. The most time demanding is a live support and I think that you should consider it only after providing support via some tickets software, there are free ones like Hesk.
It your software platform open? If so, considering creating a forum on your website. Then you can establish an environment where users support each other, and you only have to weigh in on more difficult issues or times where a legit question is not answered after a few days.