If she won't sell it for any less, then maybe just get the cheapest cage you can that is a good size for a Syrian. I think the Alaska is that probably at £34.99 (free delivery). Although you could get a hamster cheaper than that without a cage, at least you will be giving the hamster a better home. Someone else might buy him and keep him in that cage with that wheel. The cage could be useful as well for playtime, as a pet carrier or for cage cleaning.
Alaska Hamster Cage | Free P&P on orders £29+ at zooplus!
You would need a Syrian sized wheel as well - this one is good value on Zooplus - you'd need the 28cm. If you bought it at the same time as the cage you wouldn't pay postage for it.
Small Pet Exercise Wheel | Free P&P on orders £29+ at zooplus!
You wouldn't need much else. The house on the shelf might need taking out as the holes in it are a bit small for a syrian, but the shelf is fine without it. If you don't have a house then a shoebox house can be good
Plenty of space for a big nest and you just cut a door in it.
You could use some of the toys from the small cage as well - there's a sputnik in there which could hang over the Alaska shelf, and you could use a couple of the tubes from the small cage as floor toys in the Alaska. Then you just need lots of deep substrate and you'll have a happy hammy. Looks like there is already a water bottle and food bowl too. These toys and extras can add up and you usually pay about £12 for a hamster, so you'd be paying £18 for a few toys and a play cage/cleaning cage.
I'd offer her £28.