How about this, keep your current fridge :-
ASDA already have a record of what you bought - the unique till receipt no. links to a list that itemises your purchases, you can even use this yourself for their price guarantee, and I suppose other retailers must have the same data capabilities for their own stock control purposes, we just need access to this data ourselves.
Most supermarket produce has a barcode/qr/rfid tag.
I propose a standalone tablet style display-multiscanner (bar+qr+rfid+scales+imaging camera) that you can quickly book-in stock by entering the till receipt id, the shop has already scanned the items anyway.
Also, the ability to :-
1) enter items bought elsewhere by either scanning in or manually entering them by text or image.
2) define a storage location i.e storecupboard, fridge, freezer etc. (when I buy butter 1 goes in the fridge, the rest go in the freezer, same with bread).
3) set a re-order preference for a particular brand or generic/own brand i.e Fairy or any washing-up liquid.
4) record/set a date of entry - can be used to alert expiry date/age of produce.
On usage the items can be easily scanned or weighed to deduct them from the stock inventory, allowing for either unit or partial pack deduction i.e. 1 apple, 1 box of dishwasher salt, 87g frozen of peas from a 1kg bag, or 2 OXO cubes from a box of 12.
If you can set max/min & over time the mean stock levels for items then eventually you should be able to predict daily, weekly and monthly shopping lists, as well as getting reminders that you might want to transfer butter from the freezer to the fridge so it's defrosted before the current pack runs out, and that you've still got that tin of chickpeas in the cupboard from 5 years ago (do not re-order flag set!) :)
For an IoT angle, the ability to link to a price comparison site could give you a preferred supplier & estimated budget planner, with the ability to generate a tailored shopping list that could be placed for collection or delivery if required. You could even have a meal planner and get the system to suggest ideas based on the available ingredients, it could even calorie count your meals.
Shouldn't be too difficult to use current information processing & hardware technology to put this in a domestic setting at the sub-£100 mark, at the end of the day it's really just an epos type till entry system without the cash handling and small database stock management system, you could even have some of it "in the cloud", I'm sure that Google or Facebook etc. would love to have more information about you.