In the near future I'm going to have to sell my light bulbs collection, and I need to know what the proper way to ship them would be so they survive without breaking. Thanks!

encase the bulb in cardboard and then bubble wrap.  Lots of bubble wrap. 

Oh I forgot to mention, the bulbs I'm shipping will be new in package, not individual bulbs.

Why do you need to sell them?

Need money, no longer have an interest in the collection, and I need the room they are in to be turned back into a guest bedroom again and not a junk room so my mother can get off my back about her thinking I keep filling the house with junk in every room.

If they are old and rare bulbs, spray some spray foam in a shopping/trash bag and simply stick the open end of the bag in the bottom of a box, don't tie this bag just fold it over, place the lamp wrapped in another shopping bag or shrink wrap and lay it in the spray foam filled bag and repeat the foam in bag process for the top of the bulb, the foam will expand and fill in around the bulb and harden to perfectly form around the bulb and when it's hard you close the box, don't close the box before it sets or the foam might leak out of the box or worse bust the light, and you don't need to fill it right to the top as you can always toss some paper in the top of the box, and be mindful of how much the foam expands, and that the cans are single use, so if you have several lights to do get every thing ready and then foam fill the bags....

Or if they are lamps like an LPS or florescent wrap them in foam/bubble wrap and stick them in a ABS / PVC / Hard cardboard tube and tape or plug the ends, if you glue plugs on the ends drill a small hole in the pipe to allow for air pressure changes and make sure you mark and leave enough room on one end for the person getting the lamp to know where to cut the pipe and remove the lamp without damage, just stuff it with paper to stop the bulb moving in the tube.. And if your mailing stuff in tubes check at the post office, often it's cheaper to mail them if you pack the tube inside a box, the post office machines have a hard time dealing with tubes and they will bill you for that because a person has to read the labels on them not the machine...

And I know lots of people like double boxes, if they offer to pay extra for the postage and ask for double boxes, or special packaging follow there instructions, because if it arrives damaged it makes resolving any issues a lot smoother, and then you also won't end up on some ones gallery like sailermoon_01_uk mail/courier wall of shame showing there vast collection of mail busted stuff which can be viewed here http://www.lighting-gallery.net/gallery/thumbnails.php?album=4540&page=1  And if you do end up there, and you listened to there packing instructions,  they will give you a kudos for packing it well, it's hard to stop stuff getting busted if they run the delivery truck over your package...

They're all brand new incandescent and CFL's bought from 2011-2015 at retail.  Nothing rare. I do not have sprayfoam but I do have some sheets of eggcrate foam sheets.

A box crunch up newspaper around package works well
In a box. 

For my rare vintage bulbs i double box them but I use
Waded up toilet paper. The truck is bulb need bit movement bur also allowed to be shocked asorbed.

encase the bulb in cardboard and then bubble wrap.  Lots of bubble wrap. 

Agreed. As much bubble wrap as you can get, then more. And more. Then more still.

As stated, I am shipping new unopened packs of bulbs, not individual bulbs.

I'm sorry to hear you may have to sell your lamps.
The most important thing when sending lamps is to pack them in something that is soft and springy.  The worst thing you can do is to pack lamps in rigid materials like polystyrene chippings, and sorry to say it Lodge, but even worse is to use rigid spray foam! 

Its worth knowing that the glass bulbs of lamps are specially toughened so that the external surface that you can handle is about 100 times stronger than the inner surface.  In the factories the standard test of strength of the glass bulbs is to drop them from a height of 60-100cm onto a concrete floor, and they must bounce rather than shatter.  However the tiniest impact on the inner bulb wall can cause it to shatter.

So during transport it is extremely rare for a lamp to fail due to any impact to the outer surface of the bulb (of course it should still be protected though, by a layer of bubble wrap or cardboard).  The way most lamps fail in transit is due to impact damage of the internally suspended filaments or discharge tubes.  Lamps usually fail when packages are dropped.  When the box hits the ground it stops instantly - and if the bulb is rigidly mounted within the box it will also stop instantly.  However the fragile inner components do not have anything around them to cushion the impact, and they continue moving even after the outer bulb has come to a stop.  This applies forces to the internal structure, which is by far the most fragile part of the lamp, and often wires will become bent, filaments can break, or arc tubes can dislodge and move off-centre or break away from their support frames.  This may cause secondary breakage of the glass bulb, due to an impact on its inner surface rather than the outside.

The best way to avoid this type of damage is to wrap the bulb in a good thickness of something soft and springy.  Lightly crushed newspaper or shredded paper is by far the best, or loosely wrapped bubble wrap.  The most important is to keep the lamp slightly loose inside the box - if you shake the sealed box you should be able to hear the lamp moving around slightly.  The packaging of many lamps is designed to allow a small amount of movement.  In this case when the carton is dropped and comes to an instant stop, some of the forces that are transferred inside are absorbed in causing the lamp to move slightly within its packaging.  It comes to a stop much more slowly than the outer carton, cushioned by its soft and springy surroundings, and the forces transmitted to internal parts are greatly reduced.  Packed this way, its possible to send all but the most fragile lamps by post with a very high chance of arriving intact!

Just one other note - in case of sending long lamps or tubes, never use rectangular cardboard boxes.  Cut along one of the long edges of the box, and re-fold it to a
 triangular section.  The triangle is mechanically a much stronger shape than rectangular, and there is less chance of the box being crushed or bent during transit.

Thanks for the help, James.  And the USPS does have triangular shipping cartons long enough to carry a golf club. (I don't have any fluorescent bulbs)  I have a lot of brown packing void fill paper, I think that will work.

I won't have them up yet, but I will notify people on here when I do in case it is something someone here wants to buy.  I don't have rare or vintage bulbs, its all stuff from the last 6 years.

Making the storage room they are in into a guest bedroom again is more important than hoarding light bulbs. Just trying to make my house clean and not looking like a hoarder's house again. Gets tiring having to move so much stuff just to get into a room, or having stuff fall over behind you.