I think Paypal absorbing 3.5% of transactions is excessive when you're buying/selling custom pieces ranging in the thousands of dollars. For them to assert flat fees on a scale based on purchase price would make more sense, to me at least. It's a double whammy when buying selling on the Bay, where you're being charged by both Paypal and the Bay.
On smaller purchases, no, I don't think it's unreasonable. I find Paypal convenient and expedient in all instances.
I'm guilty of requesting addition of the 3.5% rather than simply building it in, since I've sold things by example, having seen others do this for years. I intend to change my practices, however, to build the price in, as I see everyone's points in this and similar threads. I'm also not too stubborn to change at 38 years of age.
Prof.
I have spent many, many hours searching for an alternative to PayPal, and I hate to sound like a shill, so if anyone knows different from what I say below I would love to be set straight.
Check with your bank or other major card processor and see what the requirements and fees are to process credit card payments. You will have monthly fees for equipment, minimum monthly fees for the privilege, and in addition to the roughly 2.5% base discount rate, 3.5% for Amex (also charged on the entire purchase price with no "ceiling" just like PP) you will pay additional fees ranging from .5% up to 2% or more when your buyer uses a credit card that accrues "miles", "points" or "rewards" towards all kinds of neat "free" things for them (someone has to pay for that, and it sure ain't gonna be the bank). There are additional costs/fees to be set up to accept credit card payments through your own website as well.
The number one shortcoming of every other credit card processor I can find, and makes the PP fees almost trivial? ZERO "seller protection" for online transactions. Which means if you don't have the cardholder and his/her card physically presented to you and you swipe it in your terminal and have the cardholder sign a receipt for the purchase, the cardholder can claim he didn't authorize the purchase and you will (in all likelihood) be left using the legal system to try and recover your money/property. Even PayPal doesn't protect you when you use their service designed to take payments over the phone.
It does take a few days to transfer money from PayPal to your checking account, but there is no charge to do it.
I have found PayPal to be superior in almost every way I can imagine to traditional card processors for a small business that primarily does business online or over the phone.
YMMV