I don't think it sounded like she was being mean...
1. you buy a trailer with out taking a mechanic or some one that knows about them.
2. You never asked the owner to hook it up and prove to you that everything worked.
3. People here are trying to help you,you got what you paid for because you were he a big hurry to have a trailer. If the brakes and bearings are the only thing you need to replace then you have redone half of the most major parts.
300-500$ to restore a older trailer isn't bad. Your biggest expense are the proper rated tires for them...You just can't put any old tire on them if you want to keep rolling.
Most here are experience trailer owners Me for 30yrs. The best thing you can do is get someone who can change brakes on a car or truck to do it for you.It's not hard to do you can measure the old drum and brake shoes to see what size you need. If not sure take the old one off and take it to the parts store and they should be able to match the parts. You can download instructions from DIY sites
Oh act your age I also thought you were young.