Reading hotel reviews, comparing flight options and exploring top attractions are critical vacation-planning steps to nail down a trip you and your travel companions will enjoy, but the financial aspects of your itinerary must be considered, too. Remember, the perfect vacation isn't just one creating lifelong memories – it's one that won't leave you worrying about draining your wallet. After all, if you spend more money than you budgeted or you fail to account for extra unexpected fees, you could arrive home with an empty bank account – or worse – a huge credit card bill.[See: 10 Outrageous Fees Every Traveler Should Know About.]Creating a comprehensive travel budget isn't hard, but it does require a little legwork and planning. While there are obvious travel expenses such as hotel rooms, airfare, car rentals, train travel, airport transfers and meals, what about everything else? Here are a few hidden vacation costs to keep in mind to avoid bursting your budget.Checked Baggage Fees While some airlines don't charge checked bag fees for your first or second bag, others charge $25 or more for each bag you don't carry on the plane. Check with your preferred airline to see what they charge for your first and second bag before you book. Also, keep in mind that certain co-branded airline credit cards give you your first checked bag free. Airline Seat Selection FeesWhile some carriers let you choose your seats in advance, others make you wait until 24 hours from boarding to make a seat selection. You can pay anywhere from $5 to $80 to get your pick of the best seats early on. And while getting an aisle or window seat may not be important to you, it's a smart idea to select your seats in advance if you want to sit nearby or next to your travel companions.Priority Boarding Boarding early and jumping ahead of other passengers is another overlooked perk that can cost you. Most airlines will let you pay $10 to $15 per leg to get on the plane prior to other fliers. Southwest Airlines, for example, allows you to pay a $15 EarlyBird check-in fee that will land you in the first boarding group. Taxes Hotel occupancy taxes aren't anything new, but they can sneak up on you if you don't plan ahead. Some occupancy taxes are included in your nightly room rate, while others are paid on arrival. In Rome, for example, tourists are required to pay a tourist accommodation tax in cash by the day based on their selected hotel. A five-star hotel, for example, costs 7 euros per person, per night. Excursion and Tour CostsPlanning a guided bus tour or a guided hike through the jungle? Don't forget to budget for the price of these excursions, as well as transportation costs to get there. Cruise excursion costs, whether you choose to book with a cruise line or on your own, can be especially pricey, so research your options before your trip to avoid sticker shock.[Read: 8 International Trips Under $2,000.]Resort Fees Some hotels tack on resort fees to cover the costs of pool and gym usage along with in-room Wi-Fi access. In Las Vegas, resort fees can add an additional $50-$60 to the cost of your nightly room rate. Since these fees aren't always included in the advertised price of your hotel, be sure to ask before you book. Also, make sure to inquire about charges for internet usage. In the absence of a resort fee, you may need to pay a daily fee to access the internet in your hotel room. Car Rental Insurance Depending on where you rent a car, you may be required to buy mandatory rental car insurance. However, some rewards credit cards offer this perk for free, so make sure to explore your loyalty card's benefits before you book.Parking FeesIf you're renting a car or bringing your own vehicle, be aware of the various parking fees you'll encounter. You may not only need to pay to park your car at your hotel or resort garage, but also for parking whenever you venture out as well.Sunscreen The cost of sunscreen can be overwhelming when you're slathering your family several times per day for a week straight at a tropical resort. To trim costs, buy sunscreen at home and bring it along with you.Passports If you're planning an international getaway and need to renew your passport, plan to shell out around $110. And if you're planning a family trip, keep in mind the cost for renewing multiple passports can add up quickly. Currency Exchange FeesIf you plan to exchange your currency once you arrive in another country, you should also plan to pay a percentage for the privilege. Withdrawing money from an ATM might help you save on exchange fees, but you may get slapped with an out-of-network ATM fee instead. And to avoid pesky charges for purchases made outside the U.S., also consider using a credit card without transaction fees. [See: 10 Common Pieces of Travel Advice You Should Never Follow.]Final ThoughtsTo avoid overspending on vacation, take a close look at your entire itinerary to look for spots where you'll need to bust out your wallet. Travel is never cheap, but it's much easier to endure a high price tag if you plan ahead.