do it yourself. it's easy enough to do. if your bearings aren't bad you just clean and re-pack them. new seals are 10.00 or less. just don't forget to chock the wheels on the opposite side so it won't roll over you and maim or cripple you.
It is very easy to do it yourself. I just did two tandem axle trailers this week and have ten or more to go through as I get time. Northern tool will have everything you need but I like to go to southwest wheel in downtown as their quailty is better and the price is still really good. If you have any questions about it shoot me a txt or pm and I will see if I can help out.