If Nintendo started selling bells...
So I was just thinking, how much do you think a bell is worth in the Animal Crossing game? If I was to stand at the Animal Crossing counter with £100, how many bells would the cashier give me?

It might be easier to answer how many bells Nintendo would give you for it, if they started selling them as "add-on" packages via the e-shop. Although it would be pretty cool to live in the Animal Crossing universe, aside from the fact I'd be bored after the first week.
If we refer to previous dlc, Fire Emblem had a map that was $2.50 american currency, in which you grind for a bunch of money. I feel like if Nintendo did something with animal crossing similarly for $2.50, you would get an option to obtain bells instead of medals on the island, or add a mini game which gave you bells.