Those Gilbarco's from the 60's (Yellow one) fetch about 500.00 when complete. I just passed a double (or twin model) that was in nicer condition offered to me at 1500.00 as they aren't high on some peoples radar for style. The others look pretty rough from the pictures so I wouldn't jump on them to quickly. Most everybody strips the pumps out. For one they stink because of residual fluid in the pumps, and also because they weigh a lot with that old pump inside.
A good complete electric pump from the 40's through 60's is what you probably want. Visibles or Clock Face pumps are from the earlier periods and are quite often a lot more money. Un-restored electric pumps with everything there and not rotted out or rusted through can be bought in the 500.00 to 1000.00 range, with the sought after pumps sometimes going as high as 1500.00 in nice original condition. Restored they can be double or triple that depending on the quality of the restoration and the model of pump.
Popular pump series from that Era include the following makes and models.
Tokeheim 39 or 300 (tall or short)
Gilbarco 96 or 900 (tall or short)
Bennett 100, 700 or 900/1000 (short pumps)
Bennett 541 Tall (tombstone style)
Wayne 60 or 70 (tall pumps including wide bodies)
Martin Schwartz 80 (short)
National A38 or A62 (tall or short)
There are many other models and you should look at your cost to buy, cost to restore, and final value before jumping on something. Pick a style of pump that suits your liking and then go hunting. Some good information for restoration parts and models can be found by visiting www.vics66.com
If you Google any of the above models and search the images tab, you'll get dozens of pictures so you can see what they look like once branded. The beauty is that a pump can have almost any brand you want on it. Esso, Texaco, Shell, Mobil, B/A etc etc. Just paint them the right color for that brand and put a decal, porcelain sign and a globe on it and away you go. Many parts like the hoses, handles, body trim, glass and signs can be purchased through restoration suppliers or by hanging around the forums looking for nice original parts. Happy hunting.
Hope that helps you.