No rules against it. You certainly can sell a website. Lots of people do it.
Yes there may be some rules. Many free themes require you to leave the footer intact so it's not really free, so you are helping them with a back link. Some free themes are free for personal use but not for commercial use and so on. Other free themes or plugins may contain viruses so be careful where you download them. You should check the README.tx or license that came with it.
Yes, This is what I do for a Job!
Rules... Not many...
Manners... When using someone elses stuff... Credit them for it!
Also I Will be starting a forum and Blog for this type of people!
InstantPrime.com (currently my Website selling site)
Hope this helps!
Justin
There are even themes such as the White Label editions by PremoPress set up to do just that and even amend them to as if it was you that created the theme. Their latest is WP Directory Suite.
Yes you can sell it by listing your site in : https://flippa.com/
tricky step. seek from bing and yahoo. that will will help!
I want to sell a website that I built using templates and themes in wordpress. Are there any rules against selling websites built with free themes and plugins?