Boy, at those prices I could be a multi millionaire in a couple of months.. That is more than what it would cost to replace the entire axles!
Shouldn't cost more that $50-$60 per wheel, tops..
First, nothing special about servicing trailer axle bearings, uses exact same procedures as any automobile wheel bearings as far as cleaning and regreasing the bearings.
I learned how to service wheel bearings on 1970's cars, trailer drums and bearings are essentially one in the same as a drum system on older vehicles.
SOOOO..
Call some AUTO REPAIR SHOPS, should be able to find at least one in your area that understands how to work on drum type brakes..
To give you a head start,
HERE is a Yellowpages search for auto repair shops in Milwaukee area..
Never take a trailer to a RV/trailer dealer for this service, it will cost you an arm and leg..