In Poland we have a saying which warns you about buying the cat in a sack. If you're paying upfront for a design you haven't seen yet, you just don't know what you're going to get.
Imagine spending your hard earned dollars on something else without first seeing (or testing) it. How about a car? Would you pay someone to make you a car if they told you. Hey, I've built many cars before. Give me some money and I'll build you one as well. I didn't think so.
Those who do, often end up hating it and ask for their money back. Unfortunately if there are no free trials and no money back guarantees, you might end up getting stuck with a sub-par actor website.
Go for the free trials. Go for the 30 day money back guarantees. Go where there is no risk. If you don't like it, oh well, it was free, close the account and go elsewhere. Worst case scenario, you've wasted some time, but at least your wallet stayed intact.