Me, my friend and I are going on an epic journey to Monaco in a car we bought for £200 and we have no idea about how a car actually works. What should we bring with us to stop us from sitting on the side of the road for 4 days. But we only have a budget of maybe £10?
I probably should have asked Halfords but you said 'Ask me anything!' So I did.
In four days the two things that are most likely to happen are a puncture or some kind of leak in the radiator, resulting in overheating. Fortunately for you, there are spray kits that will fix both of these problems.
For the puncture I would recommend Holts Tyreweld. For the radiator I would recommend Bars Leak Radiator Sealer. You can get hold of both for less than £15. If you have reservations about shelling out this much then I would seriously reconsider the logic of visiting somewhere as expensive as Monaco.