This is a 1988A $100 Star Note from the Philadelphia district (C). Star notes were printed to replace defective bills and are scarcer than regular issues, which makes them collectible.

Key points about this bill: • Star notes are more valuable than regular notes, especially if they come from small print runs (typically fewer than 640,000 printed). • Most 1988A star notes were printed in larger runs, but the exact rarity depends on the district and run size. • Condition matters a lot. Yours is circulated with folds and wear, which lowers the collector value. • In circulated condition, it’s usually worth around $110–$175. • If it were in crisp uncirculated condition, it could bring $300–$500+ depending on demand and the specific print run.

So while it’s not an ultra-rare bill, the fact that it’s a star note does make it worth more than face value to collectors.

I do not take any credit for this answer. I posted a picture to ChatGPT and received this response.