I would look for a well-maintained used unit, especially for a first RV. If possible, I would avoid financing an RV (or any "toy"), but I do know others have different opinions on fiscal matters.
You will need to budget some for maintenance; how much varies some with different RVs. Tires, in particular, can be a not insignificant expense especially for a large class A; a set of 19.5" or especially 22.5" truck tires adds up to thousands of dollars. If you're not handy (and not willing to learn how to be handy), paying someone to do all the little fixes and maintenance duties an RV requires will also get pretty expensive pretty quickly; they're similar to boats in that regard. It's been said that the main difference between an RV and a boat is that the water can also leak out of the RV.
If you don't have experience RVing, I would heartily recommend renting one for a weekend or preferably a week before buying. It will help you know if you enjoy the mode of travel or not, and give you a better idea of some of the sorts of things that matter to you in looking at various models. (Do you prioritize a larger shower or more kitchen counter space? Is the arrangement for dumping tanks convenient enough for you use easily? Is there space to put a trash can?)