If people drop stuff off to have it packed it is extremely expensive. You know that now. The cost may depend on weight and package size, so it may not be possible to post the rates. I believe UPS stores are independently owned and operated.

I would NEVER settle for someone saying "a small fee." Even if the person walked away, I would not engage in the transaction until they told me. They may not have been able to say exactly, because the final weight might be unknown. However, they should have been able to tell you this would be $15-20.

I once bought something on ebay and the guy said he charged "actual shipping costs". He wanted $40 to ship a laptop computer. The reason? Packing by a UPS store was $18. I told him I agreed to pay for shipping, not packing.