How do I set money boundaries with friends without sounding cheap or controlling?

I grew up in a pretty frugal household and, even as an adult, I track prices like it's a hobby. I'm not struggling financially, but I have specific savings goals and I feel a lot calmer when I know what I'm spending.

Lately my friend group has drifted toward more expensive hangouts - nicer restaurants, concert tickets, group gifts, weekend trips. I really like these people and want to be included, but I keep falling into two bad patterns:

1. I say yes, then stress about the bill the whole time and feel resentful afterward.

2. I try to steer everyone toward cheaper options and it comes off like I'm policing the group or judging their choices.

Last week someone suggested a birthday dinner at a place I know will be pricey. I froze and made a joke about how my brain only thinks in coupons, which didn't land well. Now I'm worried people see me as the annoying friend who makes everything about money.

What's a simple, non-awkward way to say I have a spending limit without making it everyone else's problem? And how do I bow out of expensive plans sometimes without slowly getting invited less and less? Any phrasing or approaches that have worked for you?