Pretty much how the money transfer works is like this:
Buyer pays PlayerAuctions according to how much the offer is listed as. For example, if the offer is 100m for $100, than the buyer pays $100. No extra fee's are incurred upon the buyer.
After PA verifies the payment, they give the go ahead to the seller to transfer/deliver the product specified to the buyer.
After doing so, both parties confirm delivery. Although not filling out feedback leaves the order under the "Active Orders" tab, once both parties have confirmed delivery the payment is processed.
For Runescape, the fee's charged to the seller are 9.99% + $1.99. To see how much money you'll be receiving from any particular trade, simply utilize the following equation
(X Amount of $$ of initial listing) x (.9001) - (1.99) = X Amount you will receive
Below is the procedure of how a PA offer is carried through.
As you can see, the buyer pays PlayerAuctions, and then PlayerAuctions pays the seller. 2 seperate payments for 1 transaction. Therefore, the seller is safe from any and all chargebacks the buyer may initiate, since the buyer's money was sent to PlayerAuctions. Them being a reputable company with extensive trading history have a much higher chance of winning any disputes brought upon by the buyer.
It's 100% scamproof for both parties, as the seller is subject to the buyer's money if they have proof of delivery if the seller tries to cancel the order.
The seller is subject to a refund if the order takes longer than 72 hours, or if they buyer doesn't deliver. They simply cancel the order and the money will be refunded unless the buyer enters a dispute (The buyer needs to submit video/screenshot proof of delivery, or they will lose the case and the money will be refunded.)
I personally have pushed over $8,000 worth of RSGP via PlayerAuctions (Gf $1000 to fee's) but in the longrun I personally believe it was worth it. Because if I sold $8,000 worth of RSGP via direct paypal, chances are I would've been charged back much more than $1,000.