Read more closely. You missed the "...or couldn't get it" The ability is more valuable to me than the certificate. I let mine lapse almost a decade ago. I got it, that's all that matters to me. I got the 30 semester hours, that is all the monetary benefit that I wanted from it. I'm not willing to pay $6.00 an hour to someone I don't trust, let alone $30. I use the word "should" a lot in that post. A lot of things "should" be different. A tech "should" be worth what his qualifications say he is worth. NRRPT certificates only mean that you passed a test once upon a time. What they "should" mean is that you were vetted by the qualification process before you ever sat for the test. Unfortunately, lots of power plants are very proud of those plaques with the names of all their NRRPT technicians on them. They want them to be full of names. So, when it comes time to sign a recommendation, they sign as many as they can instead of asking whether the tech was really qualified. What you end up with is a bunch of technicians who are qualified "on paper" to take the exam, who took a prep course (which is a virtual guarantee of passing the exam) from someone on the board of examiners, and passed the test.
If you have 5 years as a Sr. HP and you can't get the NRRPT, considering how low the bar is for getting it, you shouldn't be working as an HP. Now, if paying for the course and the exam fees are an issue, that is not an indication that you lack ability; it is an indication that you are not a house tech who can get the employer to pay the way. Unless you are going to need the college credits for a degree, taking the NRRPT on your own dime makes no financial sense whatsoever. By the time you pay for the exam, and the prep course, and the study materials, you won't work enough hours in those two years to do better than break even. At $1/hr times two years at 25 weeks a year at 72 hours a week, you end up with 4400 dollars. That assumes that every job will pay the $1 bonus, and that you are not otherwise qualified for that bonus. It assumes that you get 72 hours every week, and that you actually work 25 weeks in both years. It assumes that you take the exam at exactly the 5 year point and get your results almost immediately. If you are a full-timer at 40 hours a week, it comes out to the same amount. Once you hit your 7 year point it becomes moot because those utilities pay you the $1/hr anyway.
Of course, the fees for the exam and membership are tax deductible to the extent that they exceed 2% of your AGI. If you are tracking your expenses properly, you should be able to deduct at least some of the cost. And, if passing the NRRPT is a condition of getting a promotion or a real pay raise (not the roadie $1 bonus) I say do it if you can.
The original question is how much is it worth in dollars to be an NRRPT. The answer is : It depends. If you are looking to get a job that requires it, it is worth tens of thousands of dollars. If you are working as a roadie, it ain't worth a bucket of cold spit. If you are a house mouse, who cares??? It won't cost you anything anyway so take it!!