Every front wheel drive-type vehicle I've owned(and that's been quite a few) have needed CV joints roughly every 100k miles, give or take. But I am surprised you had no warning.
I was able to get complete rebuilt axles for my Subie for $60 each exchange at Schucks. NAPA wasn't much more.

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past MB rides:
'68 220D
'68 220D(another one)
'67 230
'84 SD
Current rides:
'06 Lexus RX330
'93 Ford F-250
'96 Corvette
'99 Polaris 700 RMK sled
2011 Polaris Assault
'86 Yamaha TT350(good 'ol thumper)