Hello! I've had a premier account for about a year now, so I'll try to answer some of your questions... First of all, you do not need a premier account in order to accept payments. You can accept instant bank transfers and echecks with a personal account. However, you will need a premier accout to accept credit or debit card payments.
When you receive any sort of payment with your premier account, you will be charged a fee (https://www.paypal.com/cgi-bin/webscr?cmd=_display-receiving-fees-outside&countries=
). The fee is taken directly from the money that was sent to you. For example, today I received a payment for $14.45. The fee for the transaction was $0.72. Paypal took out the fees before putting the money in my account, so my balance is $13.73. Fees are a bit higher to accept money from other countires, but for the most part, the fee is between $.50 and $1.50.
I used to sell on Ebay with my personal account. Even though I would always mention in the auctions that I couldn't accept credit cards, people would always try to pay with them. It was a pain to always have to deny payments, arrange for a different method of payment, etc. I had a few people back out of transactions because of it, and I'm sure I lost many other customers simply because I couldn't take credit cards. Since I upgraded to premier, my sales have multiplied tremendously (though I'm sure that isn't *entirely* due to accepting credit cards). I most definitely think that it is worth the small fee!
Hope this helped, let me know if you have any other questions!