tRump with a telling question, Badtux has a good suggestion, and EBM offers some good advice...
A very long time ago I was once accosted by a fellow cruiser who took exception with the fact that I would, from time to time, do paying work for other cruisers. Apparently, he thought, that asking to be paid for (let's say rebuilding a toilet) was counter to the whole cruisers "we're all one big loving family" vibe. I'm pretty sure that he also said I was a greedhead exploiting and ripping folks off. It still rankles...
In my defense, when working for other cruisers I always used a system of sorts which boiled down to that if someone just needed some help or advice there was never money involved but, if they were perfectly capable of doing the job themselves, then a reasonable payment for the work in question would come into play.
Of course, back in the day, things and cruisers were a whole lot different (Hmmm, I just channeled my dad)...
For starters, most cruisers were a whole lot handier and had a lot more experience in the manual arts. Which is not to say that there are not a lot of cruisers today who know how to fix and build stuff but they are a much smaller percentage of the overall cruising community than they used to be.
Boats were a lot smaller as well. Offhand, in the early 90's, I'd hazard a guess that the average cruising couple's boat was right in the 30-32 foot envelope. Sure you'd find the odd couple on a 50 foot or larger boat but they were few and far between.
And, maybe the most important difference in cruisers today and in days of yore is there is a huge difference in the amount of money in play. So much money in fact that it's hard to imagine how anyone on a blue collar budget could manage at all.
Which, sorta/kinda, brings us back to the whole working for or marketing to cruisers and being a greedhead thing...
Listening to Coverville (always a good listen).
So it goes...