How do I use this for myself as a teachable moment?

For the next time I suggest you stick to what the project included: developing a site for them.

Two things I see here:

1. You are charging a small amount of money, which ironically can have the effect of making people say "whoa, what a bargain! Let's see if I can get more out of it", and in a way not appreciate the job being done.

To prove you are "legit" you don't need to do cheap work, you need to deliver good-quality products (which you seem to do).

2. You gave this client many extras. All that support, training, changes, etc.., when you actually charged and planned for a simple responsive site. You were not obliged to provide all this support, or at least you could have charged a bit more for doing so.

This resulted in changes (which require more time from you), friction, and a bad time for you. IMHO, the hardest part of Software development is to stick to the features agreed without many changes from clients. If you give them room, they will want to redesign and include "some minor changes" every time you meet, which makes finishing a product a nightmare. The time for changes is after the product is finished and before the next iteration.

Do I fire him? Do client training to explain that he's getting a good deal/real work actually went into the invoice?

If you fire him is up to you, but it seems to me that this has already been a negative experience for you so far, and most likely prone to continue.

Another option could be to be a bit more firm and objective with the service you are providing, so this client doesn't take advantage of your good work. If he wants coaching and tutoring that would be another service that should be charged independently (or included in the price).

Bottom line, in future situations, don't confuse charging small money with delivering good-quality work. Sometimes people don't appreciate or value what they get if they don't have to put effort or resources to get it. As the Joker once said: "If you are good at something, never do it for free"

How do I use this for myself as a teachable moment?

For the next time I suggest you stick to what the project included: developing a site for them.

Two things I see here:

1. You are charging a small amount of money, which ironically can have the effect of making people say "whoa, what a bargain! Let's see if I can get more out of it", and in a way not appreciate the job being done.

   To prove you are "legit" you don't need to do cheap work, you need to deliver good-quality products (which you seem to do).

2. You gave this client many extras. All that support, training, changes, etc.., when you actually charged and planned for a simple responsive site. You were not obliged to provide all this support, or at least you could have charged a bit more for doing so.

   This resulted in changes (which require more time from you), friction, and a bad time for you. IMHO, the hardest part of Software development is to stick to the features agreed without many changes from clients. If you give them room, they will want to redesign and include "some minor changes" every time you meet, which makes finishing a product a nightmare. The time for changes is after the product is finished and before the next iteration.

Do I fire him? Do client training to explain that he's getting a good deal/real work actually went into the invoice?

If you fire him is up to you, but it seems to me that this has already been a negative experience for you so far, and most likely prone to continue.

Another option could be to be a bit more firm and objective with the service you are providing, so this client doesn't take advantage of your good work. If he wants coaching and tutoring that would be another service that should be charged independently (or included in the price).

Bottom line, in future situations, don't confuse charging small money with delivering good-quality work. Sometimes people don't appreciate or value what they get if they don't have to put effort or resources to get it. As the Joker once said: "If you are good at something, never do it for free"