Yes, you are.
The £88.50 price is only if you apply online. Using a paper application is £100. IoM doesn't have an online application option, so you pay the same paper application cost
I don't see the point of Teso doing a price check with Aldi. I thought the whole point of these things was to show that it was no cheaper at the other store, so there was no point in going there. As there isn't an Aldi here, why do the price check?