Serpentine belt is $29 from IPD. Tensioner is $64.
To replace both is an hour or so, tops...
$200 - $250 seems reasonable to me...what are they charging for parts/labor?
2006 Corolla (kid's car - 132K, Eco Contacts, Castrol Edge 5W30)
2005 MB S600 (74K, Michelin AS3, M1 0W40)
2002 V70-XC (178K, AltiMax RT43, Pennzoil Ultra 5W30)
2002 V70-T5 (161K, IPD bars, Bilsteins, Extreme Contact DWS, Mobil 1 0W40)
1992 MB 300E (Sportline - 137K, Yokohama Avid, Liqui Moly 5W40)
1990 4-Runner (V6, 4WD, mild lift - 250K, 31" BFG AT KO, QS 10W40 syn)
1932 Packard Sedan (straight 8, dual sidemount spares, original paint and interior, Shell Rotella 15W40)