1. Look at GW's website and check out all the armies, see what you like. Most have a start collecting box.
2. Check on YouTube. I like 2+Tough for lore.
3. I have enjoyed them alot, can probably find a thread here about specific books others have liked.
4. There are third party sellers that offer discounts, but cheap is relative lol. Youtube has a ton of videos of paint comparisons, the usuals are Citadel, Vallejo, Reaper, Army Painter, and some others.
5. Picking the army that you think is the 'coolest' is usually going to give you the best experience. Watch lore videos on armies that you think look cool, watch some battle reports on youtube(I like Rerolling Ones). Maybe look into skirmish, it's a cheap book and some new rules in January's white dwarf sounds like. That way you can plan to build up a small warband first to not get overwhelmed right away. Depending on what army it could be like 5-20 models is all. I'm sure someone else will have some more and better advice for ya.
*just enjoy yourself and don't worry about speeding towards having a huge army super fast. Watch painting tutorials on youtube. Go to your local store and talk to people.