For what it's worth, I think it really depends on what you're going to do with the game. I bought the starter set for the adventure and the monster stats (retail $20, I think I paid $12 on amazon), and between it and the Basic PDF I am probably set for at least 6 months. I'm just playing once per month or so with my kids, though. The basic rules will take you 1-20 with four classes and four races, which is plenty for us. Once the monster manual comes out in september, basic dnd will have its own small bestiary too, which I could probably use and reskin indefinitely. I may eventually buy the big 3 books (maybe?), and I'm sure they will run less than $50/pop on amazon ($30, $35, and $35 on amazon right now as preorders). I know that's not supporting FLGS's, but it is what it is.
I enjoy running published adventures, so I could just buy adventures from here on out and be just fine with only the Basic package and none of the big books. If my kids find that they really want new characters, maybe we could get the player's handbook. ::shrug::
I think 5e is a pretty fun game. It's fast and fun, the mechanics are interesting, and I like the style of gameplay the speed & simplicity helps cultivate.. I love how backgrounds are implemented to help players both flesh out characters and customize them skill-wise in any direction they prefer.
Pathfinder's a great game too, but I'm enjoying playing something a little different.