wheelybugs advise please

hello,I am crashing over from a baby forum,although it will not be long before I join you-my Lo is 1 this week!I cant believe this!!!Anyway,I would like to buy her a wheelybug but am finding them a bit confusing.They are large and small,but some of the large ones says they are suitable from 12 months?I have to buy it on the net,so cannot go and wiew it and really would not like to spend ??50 on something thats gonna be either small or big.Have you got one of these and what would you advise?Thank you!Martina