I tried a lot of Help Desk and settled on Crisp.

In the free version, available only Live chat with a very convenient mobile app for iOS and Android. This is usually enough for basic customer support. When there are more customers, you probably would like to switch from chatting to tickets for support and to the knowledge base. This functionality is available in the Pro, Unlimited version subscriptions. It's not free, but it's definitely worth it.

If you are a student or a non-profit organization, they give you a promo code for a 50% discount. Especially cool that this discount is permanent. You can ask someone who study. As a confirmation, you will be asked to use your student ID, ISIC, and edu email.

All the functionality is described on the price page Pricing-Crisp

We're small enough and get few enough support emails that right now, we use a Google Group for support with our team at capiche.com email address. Whenever anyone writes, we all get the email—then we can reply all so others know the email got answered. And if the person writes in with a bug or feature request, we track it in Notion (see the discussion about organizing customer feedback for more details there).

That doesn't scale that well, or rather would get too noisy and risk two people answering the same thing over time, so some other cheap ways to get a full help desk include:

• A single dedicated Gmail account for the support emails where everyone shares the login; not free if using your domain, but cheaper than paying for a help desk per user.
• Freshdesk`s free plan is wildly generous: unlimited support agents and most core features, though no automations, collusion detection, add-ons, and so on.
• Zoho Desk has a few more features on the free plan (automations for one) but it's only free for 3 people.
• osTicket is going to be the oldest/most enterprisy of this list, but it has a fully free open-source version if you want to roll your own.