Here are the fees you as the shipper cannot avoid:
- Shipping charges
All the rest are technically the buyer, unless you are sending DDP, deliver duty paid. The only fee that your buyer cannot avoid is taxes. Depending on state they are going to get dinged for taxes. That is difficult to avoid.
There is nothing that says you have to use UPS, of FEDEX for your brokerage services of a broker at all. You can usually do it yourself, it is just a pain. In this case however, your potential customer needs to do that.
https://help.cbp.gov/s/article/Article-418?language=en_US
What does matter is "who" is importing. Is it your customer, or will you be acting as the non-resident importer? If your customer, the above is applicable. If technically you are importing as a non-resident importer, then you need to look after brokerage. There are online companies that do this cheaper than FEDEX / UPS who are easy, not cheap.