I use magnets. And I love them.
When you are looking for a cheap way to a) get movement trays, b) hold the models in place during a game and c) carry them to your local gaming store, these little magnets are gold.
I use little cylindrical neodymium magnets with a diameter of 2mm and a height of 2mm (so they fit exactly under a infantery base; when I magnetise a cavalery model I use cuboid ones that are narrower but longer so they fit in the rutted base). These magnets are perfectly strong - not too weak so the model can't falls off the tray and not too strong so you won't damage it when you remove it from the tray. Such a magnet comes in at 0.12 Cents a piece.
As a tray I use 0.5mm thick sheet iron. I bought trays for both my vampire and high elf army yesterday - for 0.33 Cents total (plus 15 Euro for the cutting, but still^^)
I built a shelf of some thicker sheet metal that I put in a large bag to transport the trays with the models on them. I sinply put a slightly stronger magnet between the tray and the "board" of the shelf and everything holds perfectly in place.
This shelf will hold my entire 2500pts army with still room for more. The models will be carried around without touching anything so there will be no wear on the models. And, most important: I dont't have to put them individually into a hole in a styrofoam tray. This saves that much time!
EDIT: To get a lightweight "shelf" for transport, build it out of aluminium or plastic and attach a metal-foil that can be magnetised.
I paid about 60 Euro for the magnets, the trays, the metal-laquer and the shelf (plus parts) altogether.
Since you said you are from Germany, I can highly recommend the following page to order your magnets. Cheapest price (the magnetic sheets or what they are called are much much cheaper than from any tabletop supply-store... Magnetfolien in German) and very fast delivery. I ordered on Monday and got them on Friday (living in Vienna; Germany will be faster even)...
http://www.supermagnete.de/
I hope I gave some ideas! But I highly recommend those magnets. Better than anything I have ever tried. Since I use them, I really enjoy each game even more. The packing at home and at the store as well as the set-up at the beginning of the game is so much faster and less complicated. I don't know how I could ever play without them!