Friendship stays warmer when plans include the person with the least flexible budget.

Friendships thin out through arithmetic more often than through arguments. When the usual plan costs more than one person can comfortably manage, they begin declining, the declining becomes a pattern, and eventually nobody expects them. Nothing was ever said, and the group simply gets smaller. The cheapest thing everyone can join is the real size of the friendship.

Suggest things that cost little and let the expensive plans be occasional. Offer to cover someone privately rather than in front of others, and if they say no, choose a different plan instead of pressing.