I am planning on selling off my GE f25t12/28&33" fluorescent tubes on eBay since I don't have any fixtures to run them in. Does anyone have tips? I will probably ship in packs of four since it would be easier. Thanks.

Usually I have only shipped full boxes of fluorescent tubes which have survived with very minimal extra packing. Those couple of times I have shipped just few fluorescent tubes I have visited local textile shop and asked to get some of those empy cardboard tubes that was used in the center of textile rolls. They probably let you take them for free(Atleast I didnt have to pay anything). Then just wrap bublewrap around fluorescent lamp and insert it inside cardboard roll, tape the ends and you got a perfect packet. Big enought roll can shelter multiple fluorescent lamp in single roll. Just remember to put some bubblewrap between lamps.

Dont wrap it tight along the entire length of the lamp. Wrap the tightness like one of the options

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or
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So that  if there is light bending force applied to the cardboard tube, it won't get as muchto the lamp inside

If shipping rare or special lamps, you may want a wide plastic pipe like sewer pipe

Dont miss the ends, let the packing be much longer than the lamp so that you can stuff it from he ends for protection

I was going to try to use one of these tubes

That looks like it would work, though I'd want to put it in a long cardboard box too. I agree that for very rare lamps, PVC or ABS pipe would be better. I would not ship any beryllium-containing lamps in anything less than the aforementioned plastic pipe.