Generally, the “boss” would be paying. However, if I initiated it or it was in an ambiguous setting, I generally would WANT to pay. Why? In salary negotiations, I always try to get what I NEED upfront or I don’t take the job. That can mean some hard negotiations. IMO It is always best for your employer to understand that the relationship is a TWO WAY street. They pay and you provide your brain and service. If the employer thinks you are under economic duress, it is emboldens them during salary negotiations. It is much better to see yourself as a valuable commodity that could be shopped elsewhere. This perception is GREATLY enhanced when you appear to have your economic house in order.