Online supermarket shopping may be incredibly convenient, but the cost of delivery could increase to £15 a time, retail experts have said.
Selecting items, bagging them then dropping them off at your door is thought to cost supermarkets about £20 per order.
So the current cost of about £5 actually seems a hassle-free, time-saving bargain, and is ideal for those parents who are constantly on-the-go.
Dr Clive Black, who is head of research at Shore Capital Stockbrokers - a retail analyst - said the charge would need to increase to £15 to mirror the actual costs of shopping online.
He said that the fairly low £5 cost means those shopping on the internet are being subsidised by fellow shoppers, including those who actually go into the stores.
Families who tend to only shop in-store, pay an increased amount for their food so as to make up for the money the shop loses though their online store, he said.
According to Dr Black, only massive increases in the cost of delivery would make the service economical for the firms involved.
Currently, Asda,Sainsbury's and Tesco offer deliveries and Waitrose and Ocado have separate home-shopping operations.
Waitrose has recently reported a 50% rise in the number of home shopping customers.
Orders from websites make up about 5% of all weekly shops, while sales are increasing by about 15% annually.
And even though online shopping is popular, most outlets fail to profit from their online operations.
"Supermarket online grocery is more of a service than a profit generator due to the cost of fulfilment," Dr Black said.
The retail expert added that supermarkets will feel forced to increase delivery charges in order to sidestep massive losses, especially as more people start to log in to online shopping.
"Online grocery without proper charging for distribution is not a sustainable model," he told The Grocer magazine.
"In the long run, the service cost of home delivery will need to be better covered if this growing channel is not going to deplete returns and penalise the poor.
"More grocery orders online may make it more economic to fulfil them, but charges of around £10-15 would be more cost covering than the present system which runs from free delivery to £6.50."