Man, that one was a while back, wasn't it? I remember being a huge huge Warhammer fan back then. I'm pretty sure I still have the additional building that came in White Dwarf the issue that campaign was released kicking around somewhere. Then I kinda grew out of it, and by grew out of it I mean I became a teenager, realised that girls were kinda interesting and that nerdery was not the best thing to have.
Then I realised that a) fuck that, I do not want to go out with someone who is that sickened by my nerdy habits, and b) nerdy ladies are far cooler than non-nerdy ones. So now I have a bunch of Imperial Guardsmen lying around in my cupboard back home. This time round, I intend on painting them properly, making them look good and all that. Putting in a lot of effort, taking my time. Also, if you are concerned about the cost and not overly worried about playing in GW stores, you could build your own vehicles etc out of plasticard - there are a lot of papercraft designs out there for them. Paying €30 for 20 guardsmen is a bit ridiculous - I remember when you could get ten for £5, and because the Irish and British pounds were close but not the same, I think Ireland was the cheapest place to pick them up for a while.
So, how did folks get involved in their Warhammer habits? I was seven, when I found a book on D&D, and also my first WD (issue 179, when Titan Legions came out). Space Marine was my first game, followed by Warhammer (5th edition with the Bretonnians and Lizardmen), Gorkamorka, and Battlefleet Gothic. I played Undead for quite a while, when Nagash was still in the army list. I guess I will buy 40k at some point in the future, when I have a bit of an army and some time for gaming.