Yeah - I distinctly remember back in 2006-2007 (My early college days) getting a 2 for $2 deal at McDonalds - 2 bacon, egg and cheese biscuits for $2. Now one biscuit (normally) is $3.89 and they run 2 for $5 specials, but seemingly way less often. Back in the day, the special was ran literally all the time, but even still the cost of the biscuit was under $2. And this is 7 years past 1999.

The Big Mac Index shows the price of a big mac in 2000 at $2.24, and now at $5.58, so that would put $1 in 2000 at $2.49 in 2020 which feels a lot closer to the actual number...but still low because everything "around" the entree has also increased similarly, if not more.