First of all u must decide which country u want to go because this is up to ur decision...
Second the activities can be : - go sight seeing
- meets my friends that i never met her except only
on the internet so this is my greatest experiences because not only im going to meet her but i will be also discovering a new culture of this country.
- just anything you want to do u can bring an example from the activites in school helps or u could just invent it more easier
Third, for your budget just think how many you want to you can say for the meanwhile in euro and you can say but ill be exchanging money in that country so ill propably change it later and know how much blah blah