Long-time readers of this blog know that I'm a very experienced programmer and a very inexperienced actor. I have three times taken on Rails projects in the entertainment industry at a discounted rate in order to get my foot in the water - maybe two and a half times, depending on your definitions. Two companies with very firm entertainment industry roots, and one which you might call half entertainment and half Silicon Valley.
Anyway, at the two companies with really strong roots, the discounted rate fell much, much lower than my normal rate. In both cases, I took on side projects - additional clients and my own business projects - to generate additional income, and had to, in order to pay my bills. In one case, the side projects paid more than four times as much as the entertainment industry project.
I got the idea to make this sacrifice from a period when I was researching career changes. I don't recall the specific books or articles, but the reasoning was that you leverage your existing skills to get a foot in the door. To some extent, that works. I learned a lot about the entertainment industry and met amazing people - but each project ended badly. The half entertainment/half tech company paid a rate nearer to my normal rate, and didn't end as badly as the pure entertainment industry projects, but it still didn't go as smoothly as it should have.
This was very disappointing.
I read a great thing online once, about why lawyers should do pro bono work rather than lowering their fee, in instances where they want to help people who can't afford them. ("Pro bono" means "for the good" in Latin and is an idiom lawyers use to indicate work done for free.) I'm going to say this reasoning applies to my entertainment industry experiments as well.
The reasoning goes like this: people will not compare your discounted rate to your real rate. Instead they'll compare it to the rate they hoped to pay. In some cases, they may even suspect you of making up a completely false "real rate" to use as a bargaining chip.
The experience of lowering your rate to get your foot in the door in some new industry carries with it all the disadvantages of being overqualified. If you're curious enough about a new industry to consider making this sacrifice, it is much, much wiser to instead tell people your normal rate, and if they say they can't afford it, offer a small amount of your time for free on a regular basis. A small team with a novice programmer will get more work done (and better work) if that novice programmer can run his or her thoughts and code by a more experienced programmer for feedback from time to time.