I usually just price my DVD/Game stuff "Buy it now" by taking an average of prices from completed listings, and let it run 7 days. I hate using Paypal because ebay already gets a big enough slice (they own Paypal), but it's so easy to print up shipping labels through Paypal, and then you don't have to wait in line at the PO - you can just hand it to your mail carrier or put it in the drop box. I buy a big pack of self-sealing padded envelopes, and add the cost of the envelope to the shipping price. I keep the shipping price pretty low, as close to actual shipping cost as possible - stuff moves quicker that way. I also put a piece of bubble wrap inside the game/dvd case to keep the disc from coming off the hub - people like that.
If I sell one of my old Golden or Silver Age comics, I have to do a lot of grading and research, so I price the starting bid at the lowest price I'm willing to take, set it for 7 days, and see what happens. Sometimes they only sell for starting price, sometimes people get crazy.