January to January of each year, in 1994, what cost $4.99 in 1980, cost $9.38.
I drove part time for Domino's from March of 1982 to late 1984, and intermittently for another year. can't remember the prices when I started or when I left, but around 1982 when I was working the most hours per week, a large cheese and pepperoni was $7.06 with tax. Now that I think about it, I was at a different store by then, and I recall the college kids that ordered from the first store I worked at in '81 ordering the absolute cheapest thing we had near the end of the month, when the monthly support money from Mom and Dad was running low - a small plain cheese pizza cost $3.96 with tax. A large plain cheese was, I think, $5.27. so $4.99 was right on the money.
In 2018 dollars, that's $12.62 and $16.79. For plain cheese. Which means Domino's and all the other pizza shops were making a helluva lot higher profit margin then than they are today.