There's no downer like budgeting for vacation -- and then still coming up short at the end of the trip. Here, a few expenses that are easily overlooked but quickly add up. Be sure to take them into account on your next trip.

Tips and gratuity: You planned for lodging and meals, but did you include the $5 tip for the bellman and the 20 percent gratuity at that 5-star restaurant in your calculations? Think about how many opportunities there are to tip -- the valet every time he brings your car, the bartender mixing your drink, the guide who gave you an exceptional tour -- and it starts to add up to some serious cash. Unfortunately, there’s no hard and fast rule about how much to set aside for tips and gratuities. You'll have to think about your routines and habits as you travel to determine when you might tip, and how much.

Parking and tolls: Parking in a big city can be ridiculously expensive. Add toll roads to the equation, and perhaps parking at your home airport, and the charges start to make a serious impact. When it comes to budgeting, go through your itinerary, day by day, to determine your routes, what tolls you might encounter, and where you’ll park. (The same could be said of public transit, if that's going to be your main mode of transportation -- how many times will you be hopping on a bus or subway, or even an occasional cab, compared to walking?) Attractions, such as museums or amusement parks, will list parking fees on their websites. Other times, you may have to do a little online digging to be able to estimate what parking for the day will cost you.

Visas and other fees: A valid passport isn’t necessarily the only thing you’ll need to get into a country. Some destinations require visas that can add up to hundreds of dollars (depending on whether you need to pay a service to expedite one for you). You might also have to pay an an exit fee on the way out of the country.

Transaction fees: We all know that using a debit or credit card to buy souvenirs or pay for meals can incur a charge -- usually one to three percent per transaction -- but, like tips, it's not something we always remember to tack on to the final cost. Of course, you can always opt for cards that don't charge these fees (check out this handy list from CompareCards, generally a great resource for credit card information and strategy). Likewise, if you need yen at the airport or euros at your hotel, chances are you'll pay a fee for the convenience. Pro tip: If you do have a debit card that reimburses ATM fees, remember to hang onto your receipts from abroad. You may have to file requests for reimbursement if the fees, after the exchange rate, isn't a nice round amount like $2.50 or $3 that the bank system automatically recognizes.

Snacks and souvenirs: We all buy them, whether or not we plan on it. No one can tell you how much to set aside for these items, but to make sure your shopping and snacking don’t get out of hand, consider bringing a set amount of cash and only using that to pay on grocery and shopping trips. When the money is gone, it’s gone.

Emergencies: This is a category that you hopefully won't actually have to pull out your wallet for -- but that you should make sure that you can. It's important to have easy access to fund for a ride to the airport (or other transit station), a way to get home, and a basic visit to the doctor. Pro tip: Pay your credit cards in full before a trip, so that you can use your full line of credit if needed, and send your bank a travel notification so that they don't mistakenly flag your activity as fraud.