How hard would it be to replace a front wheel bearing on my 2002 mazda protege? How much time and money am l looking at? Is it even worth it to do it myself, or am l better off bringing into a shop?

You will need a press to do this job yourself (or an auto machine shop that will do it for you.
Quicker would be to get a new front spindle assembly from a salvage yard and just replace it.
While it may be a used part, it should have a good life expectancy.
You will need the usual front end tools and l would plan on giving it an alignment when done.

u r asking how hard could be do it for yourself ? ur question have give the answer already.. do not attempt doing by yourself

the bearing is like 55$ & install take about 1hr so u will pay like 100 more or less for the labor

is not hard to do it but if u have never do it, that change the things , the guy above says u have to use a bench press but he is wrong, using that is the easy way but u can do it manually with a hammer & a heavy flat screw driver

i have two same year cars (protege) & it took me 25 mins for install doing manually but l have make that kind of job a LOT of times in other cars