Hello mike
1st read this:
http://www.oople.com/forums/showthread.php?t=60671
Great guide and may answer some of your questions.
I started racing mid summer this year and i am having loads of fun. I started in 2wd because that's what i had. 2wd is generally simpler and easier to get into than 4wd but takes more driving skill. but that's only what i have heard.
Good thing to do is go to your local club if you don't know which is your local club have a look in the around club talk section. once your at the club have a chat with people see what there running watch the racing ect. you might even find that someone is willing to sell you some gear.
best bet on car would be 2nd hand. also with electrics (electrics can be expensive). maybe post something in the wanted section? As with the car you may get loads of suggestions whats best but as a newbie it wont matter, as you wont be that good to outperform the car. Just don't get something that is over the top and stick to the main big brands.
best thing about being new is that hitting first jump and watching your car fly through the air for the first time.
James