YouTubers pay monthly for screen recording, captions, clipping and scheduling before the channel earns a cent. One-time tools fix the cost of production at the price of a single video's ad revenue.
The tool this job usually means renting is Submagic, at $18–39/mo — roughly $216 a year, every year. Captionly does the job for a one-time $34 — running locally on your own machine.