$20 from a few years ago would be close to $100 today which is $5 per note. Sounds like you will do just fine.
MG
Not everyone invests every last cent they have. I, for one, like to keep a bit of cash around when I want to go to Mickey Dee's or Horny Tim's. The novelty of having 20 consecutive asterisk notes, especially if you found them yourself, far outweighs the face value or the calculated inflationary value. Collecting paper money as a long-term investment strategy is not a good one.
Replacements or otherwise, consecutive notes carry some burden if offered as a single lot because not many people want 20 consecutive notes. On the flip side, consecutive notes are more likely to be perceived as Uncirculated. Convincing people that a single note is uncirculated is harder. I actually have some experience selling runs of replacements. I did the best when I sold them in pairs. Two consecutive notes appeal to a lot of people. Even the people wanting just one are OK with buying two because they are more assured of getting an Unc note and they can always sell one if they feel they must. Larger groupings bring in smaller profits per note. Single notes were really hit-or-miss and take twice as long to sell off as pairs.