Websites can bring in a lot of work, but it depends on how they're put together - i've seen some amazing DIY ones and I've seen some awful ones built by supposed professional,... so the results really depend on the quality of the finished site. If you decide to build your own, just keep on going till its perfect, don't get fed up & say "that'll do for now" - stick at it till it makes your competition jealous!
If you decide to get a designer to do it for you, make sure you discuss exactly what you need & exactly what you're getting in detail. These days EVERY new website should:
Be smartphone/Tablet friendly (Responsive).
Have minimum 5 or 6 pages - google loves unique content, and the less content you have, the lower you rank in search results.
NEVER list your e-mail address otherwise you'll get spammed - contact forms are the way to go.
Use stock photography as little as possible and should NEVER use images found on the internet without permission.
NEVER use flash animation or encoding (Beware of sitebuilders like wixx which use this as standard) as its invisible to Google.
Have basic geographic and service related keywords to help google find it.
Include social media buttons feeds if you use twitter/facebook/Google+
Include an xml sitemap, google submission & site verification.
Allow you to track visitors, hits & pageviews.
If you're paying a pro & he gives you any less than that, its time to complain!
1- do they work well?
2- how much should I be looking to pay for a good website
3- what kind of hit rate do they get...?