There's a tourist shop in kolymbia: you can reach it on good but it's quite expensive, especially for the groceries. We recommend a supermarket located along the highway. You can take the bus to reach it. In this case, the stop's called "kolymbia main road". In afandou, a village 10 minutes far from kolymbia (by car or bus), there's another supermarket with reasonable prices. If you have rented a car, we suggest it. In fact you can't rent a car unless you're 21 and plus. On the other hand taxis are a bit expensive: take them just when buses are not available anymore (from 23.30 to 6.00 circa).
You don't have to bring towels or pans with yourself because they are already stored in the kitchen. There's an induction hob instead of the normal one so make sure you are able to use it.
Giannis is very good!!!