open source CMS + pay for hosting + learning curve time = X

commercial product = (CMS - learning curve) + hosting = Y

if X > Y then buy the commercial product!

it will save you loads of time and time = money

For example:
Build a Website - Create a Blog - Squarespace
- the basic package is 8 USD; includes the hosting, the CMS, all the goodies- and that's alot cheaper than many hosting packages.

Look at the demo:
Build a Website - Create a Blog - Squarespace