I started making cakes with animal toppers and people toppers on them. People really like them, so I thought I might sell them online.  At the moment I use fondant but am going to start using sugar paste. 

Does anyone do this, and if so how do you package them securely, in a box?  I look forward to advice otherwise it's trial and error.

Looking forward to some advice.

AI find details very fragile with fondant/Gumpaste/flowerpaste plus making sure it is packed in foodsafe material and hoping it is kept dry all through its transit can be a pain.

So for mail orders I use polymer clay, a strong wire frame, superglue and I attach it to a foodsafe base. use bubble wrap and packing peanuts and be sure to add about £20 to your final price for insured postage and packing materials.

Here's a great 3-part video tutorial:

I wouldn't necessarily do everything this seller does, but I would definitely anchor the topper to a 1/2" foam square (she discusses it around the 8-minute mark)...

I think that idea is brilliant for shipping.

Good Lord, that was a lot of versapak she used in the video. That would work fine for things that are pretty solid like the topper she was packing, but not so much for flowers.

I just shipped some roses this morning. I put the wires into styrofoam, pack a bunch of polyester fiberfill around them, then wrap the whole thing in bubble wrap. Then they go into the box with more padding around them. The key is to make sure that the flowers themselves are cushioned by something that won't break them even if something else presses into that, so the fiberfill works well.