I'm a complete endurance newbie as well. Been "stalking" the endurance world for a good year now but have yet to compete- next month will be my first race!
If I had to recommend endurance tack (bridles, breast collars, reins, etc etc) in whatever color combo you want, I'd have to suggest www.thedistancedepot.com
Great site for other endurance necessities as well.
I got this custom biothane bridle/halter (bit is detachable using clips, which I find very handy!) from them with comfy matching black/red reins and I am in LOVE with it. I find the price very well worth it.
As far as saddles, others who are more experienced could probably give you better advice on this as I'm not 100% knowledgeable on the different brands (although I slowly find that I am becoming a tack hoarder
). From what I've seen, the majority of endurance saddles do not have a horn.
I have a Specialized Eurolight Saddle and find it very comfortable. Specialized is a bit pricey in my opinion and a used one may not be easy to find. But they are out there if you look and I loooooove mine.
Someone please correct me if I'm wrong, but if you are just trying to get into endurance, the saddle you are riding in now may be just fine for the time being. As long as it fits correctly, I don't see why you can't condition and compete in whatever saddle you are using now for the time being, especially if you are aiming for a limited distance ride. I rushed into getting an endurance saddle because they are so darn comfortable!