While I agree for simple purposes HTML and CSS are only needed... I completely disagree that a static (HTML and CSS) site can be user friendly. Let's think about this. Without JavaScript, you cannot validate forms (quickly and efficiently). Without PHP you cannot have workable forms in which to submit user data (comments, posts, e-mails, accounts, registration, questions, complaints) which therefore is not user-friendly because it is a hassle to do things on your site. Basically, with a basic layout, and some style, your page will be pretty to look at and that's it. No orders can be placed, nothing really can be done without some type of server language nowadays (PHP). I guess in the HTML tag you can put required in which the browser (if supported) won't let it be blank... but it isn't customizable, nor does it matter because a form without something to process it makes the form useless. PHP is slowly but surely becoming a needed part of all websites, even if for small tasks.
Yes you can hire someone, but that should only be a road if you NEED a site. IF you want the knowledge, and the skill set, trudge on through my list, ask for help on programming forums, go to w3schools, go to newboston, pm me for help and get learning. You are never too old to learn, and if it's something you are truly interested in, you'll make time for it. If not, then stare in wonder at all sites without knowing how they actually work