yup id say 100 euros would be right for a couple obviously much less if you are flying solo, also depends where you are staying or visiting.
in arillas we had an amazing meal for two of a fish platter with all kinds of fish and shell fish plus tara, a big bowl of mussels in wine and garlic and a big bowl of greek salad , plus carafe of wine a large mythos and a bottle of water, bread etc for 20 euros! i left a 5e tip and still felt i'd robbed him. the food was fantastic.
also if you go into corfu town try rouvas taverna brilliant freshly made rustic corfiot food at non tourist prices.
on the other side we ate at rex restaurant behind the liston had starters and main courses wine etc for E60 which was pretty good as the quality was top notch.
alas wife wouldnt let me drive down the trak to taverna agni so we missed it, boo hoo,
enjoy yourself you wont break the bank.