As I am writing this post (November 2016), you can book a return flight to Corfu from London or Berlin i May for less than 100 euros! And it’s not only from these two cities, there are direct flights to Corfu from many other European airports in May. Check out the websites of low-cost airlines like Easyjet and Ryanair for actual flights and prices from airports near you.
Accommodation is also very cheap, as May is the beginning of the season for most accommodation owners. You can get a two-persons studio for as little as 25 euros per night, or a 4-persons private luxury villa with swimming pool for 150 euros per night.
Corfu is also famous for its culinary tradition, which has been influenced by the many visitors the island has entertained over the centuries (Venetians, French, English etc). Next to traditional Greek dishes, such as Mousaka and Stifado, and grilled meat, you can also enjoy local Corfiot dishes based on meat, fish or vegetables, like Sofrito and Bourdetto. A meal in a typical restaurant will very rarely cost you more than 15 euros per person, and that’s including beer or wine!