I feel closest to my friends when they tell me they can't do something because of money. For example, when discussing flights and accommodations for a cross-country group trip a while back, one friend admitted that she was waiting longer to buy her tickets because prices at the moment weren't ideal. Another friend approved the Airbnb selections I made precisely because they fit into the budget she had allocated for the trip.
Have a financial reason for not being able to do spend money at all or all at one time? Tell me! Being real about money is music to my ears.
Knowing that they trust me enough to be honest eclipses any disappointment that we can't hang out. Talking about money is hard, but I would rather a friend tell me outright they can’t afford to do something, than avoid me out of embarrassment or fear that I’ll judge them. I would rather they suggest another week, or even month, that feels less tight than spend an entire dinner freaking out silently when someone in the group orders another drink and then asks to split the bill evenly.
As long as I trust that a friend's "No" or "Can't right now" isn't forever (or a passive way to phase out our friendship without explicitly saying so), I'm good. I promise. I've been there, and I'll know that I can be just as honest when my turn to beg out.
I won't pretend that being honest about money in friendships is the easiest thing in the world. A lot of it depends on the norms within in each friend group, and each person's history of talking about money. (Much of which is derived from family habits and social experiences.) My own family talked (and argued) about money growing up, but I think my own willingness to just lay things out as I got older came from a refusal, over time, to lie or to be temporarily broke when it was completely avoidable. I learned that being dishonest with own means may have put off FOMO, but it made me feel guilty, irresponsible, and even more secretive later on. It also led to missing out on other things later on.
There really is no magic solution to getting started other than to just do it — maybe that's a joking-but-serious text to a friend about what you can manage, or a question about how they are managing. Maybe it's a matter-of-fact admission that a trip is out of the question at the moment, but that you definitely want to stay looped in if another one comes up. The hardest thing to do is start, but honesty is easier when it's put into regular practice.
All my friends have different comfort levels with divulging certain financial areas. When I was little, buying certain snacks at the ice cream van or pizzeria showed which friends had pocket money. Before college, talking about our respective families' finances was a little awkward, as that determined who got more financial aid — but we did it in our own way. Within the last five years or so, we've started to share our salaries, benefits, raises, and promotions at work. More recently, as we have all started thinking more seriously about owning property (even if it seems impossible in certain cities) — or becoming more responsible for our ageing parents, or getting older with or without romantic partners — the truth-telling is in full flow.
I feel especially close to my friends when they let me know they can't hang out for financial reasons. They're being vulnerable with me in a way that I don't take for granted, and they're also revealing the priorities that they've set for themselves in the short- or long-term future. Those goals are also things we can talk about, and knowing about those areas/concerns/worries/frustrations contribute just as much to the deepening of our relationship as getting a "yes" to spend time together.
None of this honesty is a precise science. There are still times where I really struggle to be forthcoming about why I can't (or won't) participate, especially when it involves travel and birthdays. The former is the hardest for me: Even if I know a trip is too last minute/way out of my budget/less of a priority with other things I have going on, I always want to say yes. I'll say no to a movie (an easy pass), a concert (a refusal with some thought), and drinks (with a "Let me get back to you!" until I know I won’t feel bad about getting a second or third cocktail). But a trip? I'll do advanced mathematics to justify my own desires and avoid a friend's disappointment.
Turning down the chance for fun memories is hard and occasionally makes me feel like a scrub. I have friends who have both the vacation resources and financial ones to be gone nearly all the time. Still, 99% of the time when I've said I can't do something at all or at the moment, there's is another friend who will say, "Oh my god, I can't either." "Me too." Same." "Right?!" To me, those moments can be just as fun to share.