Book the best hotel and rental car deals at Booking, Agoda and Rentalcars. Thats how I usually book most of my trips as they offer excellent deals. If you want to stay in private apartments I would check out Airbnb, get a 20 USD discount. For rides within cities register here with Uber and get a free ride.
Travelling abroad often involves different means of payment. Beware, your bank or credit card might apply some really hefty charges. I found a solution a few years ago when I applied for my Revolut card. You can apply to several online bank accounts with different currencies. Compare their unbeatable rates and conditions and save money while travelling. Apply for your Revolut card now.