Good topic, sorry to revive it from the dead. Considering moving my base to the Med, started to do the maths for a 4-member
family. Not just
money, but time as well.
For us,
Croatia is within driving range, meaning we could save 500+EUR per trip on travel costs compared flying to most other Med destinations especially during high season, which we are bound to because of the
kids school holidays. This is easily 1k€ with just two
family trips (they don't always joint me).
However,
Croatia is one of the expensive countries, use it as a base for our 10m boat it would cost at least 3500€/year ("cheaper" marina+Croat sojourn tax - forget about easy accessible marinas). In comparison, in
Greece or Turkey one can find a place for around 2500€/year and the
taxes are more relaxed (called blue card for your potty in Turkey

).
Going further,
Tunisia is probably the cheapest, you can get a berth in Monastir or Hammamet for 1000€ for a 33'-er.
Everybody are welcome to translate the figures to their own boat size, but the map won't change much, just the differences grow proportionally with size.