I think that $4000-$5000 can be reasonable for going to Europe; however, this is taking into account that you find the cheapest airfare possible, pack your own snacks, and don’t stay at 4-5 star hotels.
We went to Ireland for our Honeymoon – 11 days, 10 nights. Not sure what the final cost was (after buying a few trinkets here and there), but the basic break down was:
$1680 for airfare (altogether, for both of us)
$1250 for hotels/B&B’s – we traveled from city to city and stayed in different places each night. I highly recommend B&B’s also, as well as paying for breakfast; it’s a great way to make sure you’re ready to go exploring for the day.
$450 for 8 day car rental. We got an automatic car (since neither of us drive a stick) which ended up being good anyway… a lot to focus on for driving on the wrong side of the road! If you go somewhere like London, it’s probably a lot easier to get a train/bus pass. Those run about the same price but they’re worth it.
$120 for gas for the car. We didn’t have to fill up as much as we thought we did!
THen after that, you just need money for food/drink/activities! If you have your activities planned out ahead of time, you can anticipate how much that might cost.
We stayed in some amazing places (splurged one night for a castle) and saw some incredible sights. I booked everything through booking.com, used Trip Advisor for reviews (as well as booking.com), and made sure every place we stayed provided breakfast. I also looked at maps for buses to make sure that if we needed one, we’d be close to a bus stop. All-in-all, I think we handled the finances pretty well, and got our bang for our buck!!
**Oh, and my numbers are in dollars, not euros. These were the final costs after conversion. 🙂