Outfits for subs

Let's consider this scenario. I'm approaching you on a public space, whether it be a mall or gas station or concert to buy you something.

1. What outfit of subs would influence your decision to accept the pay? I certainly know a well dressed and well groomed sub has a better chance to get accepted.

2. When should a sub offer? Before you were about to buy or during or when you're about to pay(like in the movies).

The above opportunities are like once in a blue moon occurrence so we don't want to make any mistakes.