They are totally common standard bearings. Look for a local bearing supplier. Get name brand double sealed (both sides) bearings in the standard tolerance (usually E3 for electric motor use). Double sealed is usually 62xx-2RS, if it's 62xx-ZZ that's just a dust shield and not a proper seal. The bearing number can be found on a list here in the archives somewhere or just take the old one out and look for the number, it's a 6202 or something similar.
SKF, FAG, NTN... good brand names. I don't KNOW about cheaper China made stuff but I like to stick to known good brands. They may be made in some oddball country, but if FAG puts their name on it it is almost certainly good.
For online ordering I've had super good experiences with Boca Bearings. Their website is mostly about skateboard and model race car bearings but they have everything. Don't bother going nuts with expensive ABEC 7 bearings.