The few times I used a UPS store their prices seemed to be about 50% higher than if you did it at the UPS website.
The $18+ was the cost quote on the UPS website. I use the website all the time to estimate the shipping costs. It’s somewhat higher at the UPS Store. I think it’s less than a 50% add-on though. It beats the hassle of trying to get to the hub between 5&7 am or 5&7pm. What costs out the wazoo is UPS pickup in a rural area. It’s only affordable if you ship high volume on a regular basis.