I find it funny that (at least in America) we think that in order to socialize, it needs to require planning and money needs to be spent. For some reason, we have to meet at parties, act sophisticated, and spend money on unnecessary things to facilitate our interactions. We have to go to movie theaters, see concerts, watch comedians, go to bars/clubs, participate in organized sports, etc...Not saying those things aren't fun and can't be enjoyed from time to time, but it seems like this occurs every time people want to (actually) socialize.
It's rare that we just invite someone over for a casual get together for intelligent conversation and play board/video games and eat simple food. "Entertaining" is what we call it now and it has to involve carefully planned food and ultimately more $. Any kind of spontaneous interaction like showing up at a friend's house is considered awkward and maybe even rude. Of course, I'm not sure how intelligent conversations are supposed to happen or awkward encounters when our brains are now limited to 140 characters (Twitter), or that we're trained to bitch about something constantly (Facebook). Don't even get me started on how we couldn't even hold a continuous thought when those thoughts disappear within 10 seconds (Snapchat). Meaningful, casual interaction has been replaced by (un)social media and we resort to spending money anytime we actually want to get together in real life since we're all so socially inept now.
Anyway, I think the expectations for socializing are a definite contributor as to why it's so easy to fall into the rat race and become accustomed to associate socializing with spending. Thankfully, I never fell pray to this but I just find it interesting that the general public does and that everyone hasn't realized that there are better ways to live by now.