I use a drift punch. Simply slide it in and give it a little force to shove the spacer to the side first. Then use the drift punch on the edge of the old bearing to punch it out. If the inside of the spacer gets a burr I use my dremel to smooth it out. I pack my new bearings in dry ice. No idea what it costs as I have free access to it at work. Once properly chilled they drop right in.
I will say I did not need to change mine out at 140,000 miles. In hind sight I could have left them a lot longer.
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