I've got a couple of different carriers that I've used to transport my hamsters to shows.
Ferplast Aladino Medium:
Ferplast Aladino Guinea Pig Carrier, Medium, 30 x 23 x 21 cm, Red: Amazon.co.uk: Pet Supplies
I used this one for May as she was a bit anxious in the smaller carriers, it's big enough for a Syrian and the coloured sides can help the hamster feel more secure.
I've also got two carriers made out of these plastic clippy boxes from Poundland:
Plastic Clippy Box
Vectis gave me one of these to bring James home in and he was quite content in there for the majority of the day. She'd put several holes in the lid with a soldering iron but you could always use a drill if you didn't have a soldering iron. I bought a second one as it was only £1 as it always pays to have a spare. It probably wouldn't be big enough for a Syrian but it was fine for a smaller species such as a Chinese.