The first thing to do when planning a realistic budget is to work out how much money you can actually afford to use. Work out how much money you can put aside after your earnings have paid the bills and finalize an amount that you can realistically save for travelling. If you already have money saved up, then use this as your budget. Now you have decided on a budget, you can now decide on where you want to go and what you can afford based on your budget.
This is where you need to get a piece of paper and a pen, or begin a spreadsheet on your computer.
You should have two lists. These are the names of any items to take with you or costs that you will incur and the actual figure amounts of these costs will be in the second list.
In the first list, you need to think of anything that you will need before you leave. Toiletries, suitable clothing, sun cream, insect repellent, medical supplies and passports will be some of the things on your list. You should also add to this list any tickets that you have purchased before you travel. Other things you will need when travelling include the accommodation costs, price of dining out and any souvenirs or keepsakes you might want to take with you.
Once you have come up with your list of things that you may need when you are travelling, then you should work out some estimated costs for each item and put these in the other list. You should be generous with the costs, just in case you cant find the item for the price that you have budgeted. If you find that the totals come to more than your budget will allow, you need to consider travelling to somewhere closer, or choosing a cheaper destination. You can easily find loads of information on international flying on various websites and travel forums.