I think the key is description accuracy. Be upfront about any issues the figure has, how it was stored, how old, and whether MISB MIB or loose.

Photos are ok but you are better off asking people to request pics. Unless you only have a few to sell.

As far as pricing, ebay would fetch you the higher price perhaps. I listed on Amazon, Ebay, and on TFW when I was in the states and I undersold on TFW. As soon as I put stuff on Ebay, the prices climbed.

As far as postage....that will need to be case by case, just request the buyer send you their address so you can quote them a postage price. Some buyers might want more than one figure, so then postage woukd be different which makes it impossible to list postage before hand.