I have a wonderful product which people stop and ask me about frequently - it's a bike trailer/ carrier that is like a little chariot that hooks onto my bike, can carry one or two toddlers (18mo plus) up to 45kg combined weight. It has fly netting for summer and waterproof sheeting over the top for winter. Has a large storage space behind their seat (enough for two full recycled shopping bags) and can convert from bike trailer to pram by just popping a wheel back on the front. It was seriously one of the best buys i made. Bike shops sell them for around $450 for the pacific runners, i got mine from EBay delivered to my door (Brisbane to Perth so most expensive shipping in the country!) and total cost was $250, i have now seen them advertised in KMart catalogue for around $150 - but i must admit it doesn't look as sturdy as mine. So if you are into cycling this is a brilliant way to zoom around with your toddler, carry all their stuff and get some exercise at the same time :)

Try Ebay or similar - brand new, really sturdy and no retail shop mark ups!