A crest is part of a coat of arms. Coats of arms do not belong to surnames and actually they don't belong to families, except maybe in Poland and France.
Coats of arms were granted to or assumed by individual men. In England, Wales, Ireland and Scotland they are granted by the specific heraldry authority for those countries. In some continental countries they are assumed by individuals.
There are numerous peddlers on the internet, at shopping malls, in airports, in magazines and recently I saw an ad on TV selling them like they belong to everyone with a particular surname and they don't. There are no laws regarding heraldry in the U.S. Therefore you are free to display any coat of arms you wish, but to do so without documented proof that you are entitled to it is taking on another's identity. If you have pride in yourself and your family, you wouldn't want to do that.
Anytime you go into someone's home and see one of those walnut plaques over their fireplace or on their den wall, you can pretty much be sure that it is one that belongs to someone with their surname and probably isn't evey related.
What is so bad about these scam merchants that sell them is that a family history will usually come with them. That family history will not be the same family history for everyone with the same surname. A lot of people have been misled when starting their family history because of that.
The only thing you can do is to trace your father's or your husban'ds family male line ancestry to see if either are entitled to one. Another thing you can design and have your own made up.