Are excursions on a cruise actually worth it?

[Cakedragon]

We're going on a cruise to the Med, and the excursions are going to be available for purchase sometime in the next couple of weeks. Looking at typical excursions, they are so bloody expensive for what they include - up to £100 pp for a four-six hour excursion with a coach trip, and time for sightseeing/photos. It's more expensive if there's something else involved like food/drink or some kind of entertainment.

There's three of us so it would be £300 per port if we did them all. That's just not affordable. What sort of excursions should we be thinking of doing?

@RomaineCalm that would be brilliant, thanks!

Gibraltar you can walk from the ferry port to the town centre. If you want to go up the rock, take the no2 bus from the bus stop and get off at the cable car. Cable car to the top and walk down ensuring to visit St Michael's caves and back down into town....job done!

Cadiz, again can do under your own steam but Seville is beautiful and quite inland so def use excursion for that!

On the Barcelona red bus tour I am 90% certain we looked around the ferry port.....