My sister bought a big three wheeler from a site on ebay for only £65, turned out to be end of line stock at quarter of the price and is excellent! Hauck I think is a good make, I have a small 'car' version and it's pretty tough, google this pushchair and find out more about it if you're not sure
I have a Hauck infinity and love it. There are mixed reviews if you google it although most peolple who have them like them. On Kiddicare site they are selling the Hauck Infinity Jeep pushchair with carrycot add-on for £150 last time I looked.