Be sure to get one with the appropriate SNELL rating. Also, if its for use in a car, be sure it is "SA" approved. Motorcycle helmets are not. In essance, SA rating allows for multiple "hits" (like when you roll your car and your head hits the roof, windows, roll bar etc) whereas the non sa ratings are built for one big hit.
Absolutely be sure to test fit a helmet. If you wear glasses, make sure there is room to get them in and out comfortably. If you wear a neckbrace, communicator, balacava or anything else that would impact fitment, bring it along to try out with the helmet. Like shoes, different brands vary in sizes.
After you find a local place to try one on, and know what you want, then feel free to search for the best price. Pegasus racing, OG racing and I am sure there are more to choose from.
I would strongly suggest a full face helmet, but I don't think any of the clus REQUIRE a full face.
Oh, and as th old Bell Helmets ads read: "A $10 helmet for a $10 head"
It's your knoggin, protect it accordingly!