I don't have many online resources to offer, but one thing to note is that you don't need nearly as many accesories as people will tell you.
Must haves:
-Lights (ABSOLUTELY NECCESARY, even if you don't think you be riding at night. Even for day rides, I always keep mine with me. It could always start raining, or you'll be pulled over on the side and want a flasher, etc.)
-U-Lock
If you're going to be riding more than a mile, or whatever distance you wouldn't want to walk back home, put together a basic kit either in a underseat bag or to be carried in a backpack:
-Spare tube
-Tire levers
-Small multitool
-Either a minipump or CO2 cartridge for reinflating
Everything I listed you should be able to pick up for about $80 if you shop around and find sales. The lights, ulock, and tools will last you for a long time.
One other thing is to remember that not all road bikes are created equal. Even if you want to buy one online, absolutely go in to a bike shop to test ride a few. Every shop I've ever been to has been more than happy to help people out and answer questions and size you for a bike. Find the right size (long rides are terrible on the wrong size bike) and find out what kind of bike you want in the store, then go out and find the best price for that model type. When I bought my first bike as an adult, I ended up buying a vastly different model (for less money!) than what I would have originally ordered, after spending an hour in the store learning about different things.