A cheaper option is likely QT Pro. You already have QT Pro on your Mac, you just have to pay a fee to enable the features. It was about $35 last time I purchased. I took the following from the help file on added chapters as you merge videos together in one file:
Creating a Chapter List for a Movie
With QuickTime Pro, you can create a pop-up chapter list to navigate to specific points in a movie. First you create a list of topics (or entry points), and then you import the list into the movie as a text track. When you play the movie in QuickTime Player, the current chapter displays in the movie controller. (See Opening and Playing Movies in QuickTime Player.)
To create a chapter list:
In a text editor or word processor, type your list of chapters and save the document as plain text.
Make each item very short (preferably one word but no more than two or three words) and separate each item with a carriage return.
In QuickTime Player, choose File > Open File, select the text file, and click Open.
Choose File > Export. In the Export pop-up menu, choose "Text to Text." In the Use pop-up menu, choose "Text with Descriptors."
Click Options. In the Text Export Settings dialog, select "Show Text, Descriptors, and Time"; select "Show time relative to start of Movie"; and set fractions of seconds to 1/30 (the default is 1/1000).
Click OK, then click Save to create a text file with descriptors.
Open the exported list in your text editor or word processor, and open the target movie in QuickTime Player.
Choose Window > Show Movie Info.
In QuickTime Player, drag the playhead on the timeline to find the first point in the movie where you want to begin a new chapter.
Use the Right and Left Arrow keys to step forward or backward a frame at a time as needed. Note the current time in the Properties window.
In the text file, find the first chapter title and change the timestamp just before that chapter title to the time you noted in the Properties window.
The timestamp might now read, for example, [00:01:30.15], meaning that selecting the first chapter title will jump the viewer 1 minute, 30 seconds, and 15 frames into the movie.
Repeat steps 9 through 11 until you've identified all the places in the movie that correspond to the chapter divisions and you've entered the proper timestamps in the text file.
Change the last timestamp (the one after the last chapter title in the text file) to match the duration of the movie.
Save the text file and import it into QuickTime Player.
QuickTime creates a new movie with just a text track.
Choose Edit > Select All, choose Edit > Copy, and close the movie.
Click in the main movie, choose Edit > Select All, then choose Edit > "Add to Movie."
QuickTime adds the text track to the movie.
Choose Window > Show Movie Properties.
In the Properties window, select the video or audio track you want to associate with the chapter track, and click Other Settings.
Choose the main video or audio track from the Chapters pop-up menu.
If you have a movie with alternate subtitle or sound tracks, you can create multiple chapter lists in different languages and set the appropriate subtitle or sound track as the owner of each chapter list. The chapter list will change to match the selected language.
Select the text track, then select "Preload this track" (to make the chapter track load first).
Deselect the new text track so that it doesn't display on top of the video.
The new track will still function as a chapter track.
Save the movie as a self-contained movie.
You can now choose a chapter title from the pop-up menu to the right of the timeline.
