I also recommend Dave's Trailers in Glen Burnie. His prices are very good. I bought a loadright with rollers for my 21 foot nauticstar 210 DC sport deck (deck boat) and i love it. It's amazingly easy to trailer up with it. The only set back is that you need a second person to secure the bow when you drive it up on the trailer (the boat will roll right back off unless you maintain a slight amount of forward thrust until the bow is secured properly to the wench).
I bought my boat used. It came with a used trailer that didn't really fit the boat. I like having a new trailer instead ( a new trailer isnt that much more than a few hefty old trailer repair bills).
Call around to the marinas. A lot of them by or consign the used trailers after the previous owners buy a new one. Just go over it real well with $ on your mind. Ie. Bearings, springs, winch, tires, hitch, lights, bunks or rollers, springs. chestertown marina said he would buy mine for resale if I got a new one.