The Mitsubishi dealership that I purchased my 2017 Mirage ES (manual) offers an aftermarket cruise installed for $599. Since they are 4 hours away, I have never taken them up on that. You may be able to find someone outside of a dealership that would add an after market cruise for less. Rostra is probably the most popular, and they are about $300 now.
I personally like the set up Daox created, because it makes use of the push button start area on the dash. It involves being able to enable the cruise feature that already exists on your car, and I like that, too. I haven't pursued any of these options myself, but they do exist. You don't have to say I bought a base model Mirage, & I can't have cruise. It's definitely an option that can be added.
I've driven my 2017 Mirage approximately 21,500 miles without cruise. I really wouldn't bother using cruise for most of my daily driving. I have done trips (one-way) of 630 miles, 360 miles, and my parents live approximately 230 miles away (do this trip quite often). I've never found myself uncomfortable driving the Mirage without cruise. There are times when I wish I had cruise, but I don't miss it as much as I thought I would.
My base level Mirage is pretty much stock, but I did add a Daox rear sway bar. I feel that was money well spent, & something you can do yourself quite easily (just 4 bolts).
Hope you enjoy your trip in your Mirage! My dad was surprised when I told him I bought a brand new car for under $10,000, & some of his friends still don't believe it. It's an affordable, reliable, & economical small car. Enjoy it!!!!