B'ing and M'ing

Let me describe a situation for you and then let you judge the suitable outcome.

You work in a department with a team that rents equipment. You're good friends with the team but you don't work directly with them. You "borrow" a piece of equipment and was quoted a rate of $35. Your understanding was that that was what you would pay (per day or total length wasn't mentioned).

One of their employees comes to you today an informs you about being charged. They inform you the rate is now $75 and had been $50 for several years now. You make offhand comments about not realizing that it had gone above $35 because that's what it was when you worked with them closely 3 years ago. You also thought your $35 was the going rate and when you were told that you'd get a 50% discount that it would be 50% off of $35.

In addition to this you have this equipment for 2 weeks. You make more offhand comments about "not using it for more than 5 minutes one week" and then "just a little bit" the following week. You aren't expecting to be charged for the first week and you really didn't use it much the second week.

In what business world does that even matter or make sense. You borrowed equipment and was told up front that you would be charged for it. When you "borrow" (which is technically renting) you tend to have to pay for it. How does "only used it 5 minutes" make any difference. You received a HUGE discount for the equipment already. You didn't have to go through any of the traditional hassle of renting equipment and the cost is significantly reduced and you're trying to weasel your way out of more of the cost.

To wrap up the conversation you end it with, "I'll have to check with the financial people to see what we can afford from the budget." How petty, thrifty, cheap, manipulative, and conniving do you have to be to take more advantage of your relationship with this group. Everything that comes forth sounds like you're the one being hurt/inconvenienced by this. It is as though you never expected to pay for this equipment and now that you are you're offended they even asked to be reimbursed for their equipment.