It depends on whether do you buy the site for your own personal use or purely for business.
If you intend to use the site for your business, I would strongly suggest you go and buy the site (it seems to me you would like to start an online business, correct me if I am wrong).
Reasons for my suggestions:
(1) to build your creditability and your potential clients will also trust you.
(2) for branding purposes
(3) it looks more professional too
As for getting a site is easy, but ultimately, is your quality traffic to your site determines your income.
Just to share:
Traffic + Conversion = Income ($$$)
If you have no traffic and your site do not convert into sales, you simply do not earn any income from it.
So getting a site is your first step towards your online business.
You still need to drive traffic to your site and let your site does the selling for you.
Hope this helps.