Text is usually best for this because it lets you be clear and gives them space to respond without awkwardness. Keep it short and specific: remind them of the amount & say you need it back, give a concrete date, and offer a simple payment plan. Use neutral language and put the need on your budget rather than their behavior. Since the group trip is coming up, ask to wrap this up before then and keep trip costs separate so it does not spill over. If they cannot pay in full, suggest two or three smaller payments with exact dates and amounts.
Example text you can send: Hey Sam, quick reminder about the $180 I lent you a while back. I'm on a tight budget this month and would really appreciate getting it back by next Friday. If that is tough, I can do a plan like $60 this Friday, $60 next Friday, and $60 the Friday after, and Zelle or Venmo is fine. For in person, try: Hey, before the trip can we square up the $180 I covered, I'm tight this month so next Friday works, or we can do $60 a week for three weeks. If they do not reply within a day or two, follow up with a short nudge like Just checking in on the $180, does next Friday work, and if a deadline passes, name a new one and pause any fronting on the trip until it is resolved.
