Affordable Custom Domain Email Hosting Options

I’m helping to rebuild the family business and we’re about to add around five new staff members. I’m setting up their emails, but I’ve already used the four free accounts available through Outlook. I’m trying to find another option that doesn’t require paying per email, but the best I’ve found so far is $8 per month per user, which seems steep. I noticed there’s an option for $1.49 per user per month, possibly through Ox Mail. I’m new to web design and marketing, so any advice, suggestions, or explanations would be greatly appreciated. Thank you!