There is an awful lot of consideration that will go into choosing which genealogical resources you'll want to use when you're working on your own family tree.
Your first consideration will be how much time you will have to take on your project. If you don't have much free time at all, you may want to consider using a genealogist to work on your family tree. If instead, you have loads of free time, it may be a wonderful hobby project that you can focus on by yourself. If you have a schedule that lies somewhere in between those two choices, a combination of paid websites and free sources can be quite helpful.
The next thing you'll want to determine is what kind of budget you'll have for your family research project. This is very important because there are a lot of websites that charge very high fees for access to records and some genealogists charge exorbitant fees. You can discover your family history without having to pay anything, thanks to the availability of public records. That can be quite tedious, though, and paying for quick, easy access to these records may be worth it, if you have a larger budget.
Lastly, I'd suggest that anyone beginning their family history research should always put some thought into their patience level. If you are the type of person who wants results pretty quickly, you might want to consider some of the paid sites. If you have more patience, the free sites can yield a lot of information. If you're not opposed to researching and digging for the information you're seeking, you can save an incredible amount of money.