View the source and copy the css and html across. Still takes skill and you'll want to be a good theme coder before you begin. What you won't know is when they've used a clever wp function to do something or when they've got something in functions.php Personally, I'd recommend you compare the cost of the theme to your hourly rate and work out which is cheaper. At my hourly rate buying any theme is more cost effective than trying to copy it.
i very doubt someone will do it for that price!, its even less then a pre made premium theme. custom themes cost more $500 and up. good luck
If you are going to spend $20 you may as well spend $40 or $50 and get something really cool and it will save you money & time in the long run. What about updates? You will have pay someone to continually update your custom theme when wordpress updates. If you spend just a little more you will usually get lifetime updates & improvements to your theme. Not to mention the cool admin backends a lot of the elite authors provide. Which is another question for you guys, say you duplicate a premium theme in looks & functionality which is not too hard, what about the admin backends? How do they do that? Some are minimal but some like in Avada have a ton of options.
20 Bucks, Phff, If you were to pay me to rip of a theme id take 100 bucks at a bare minimum, it's better for OP to just go buy the damned theme.
you can duplicate a wp site only form doing manually work. 1. slice design into HTML/CSS then convert it into word press.
Just clone their site and serve straight html. No need for WordPress any more at all. But yeah like everyone above has said. Just extract all the elements you need from the CSS and add needed markup to the WordPress templates.