Hi there;

Flying is rather eay with a bub. I wouldnt worry about paying more for your flight, the budget flights are just as good. You can take your own food and drink on the planes with you, and also all baby related items fly free too.... SO you can take pram, car seat, porta cot and other baby essentials with you without having to worry about excess luggage costs. Bubs sits on your lap with their own belt attached to yours. I find all the attendents are quite good with the kids and will help you out if you need it. Just remember to ask for help if you need it rather than toughing it out.
And you can rent car seats from car rentals but you can also use yours too if you take it with you....