yes that is a good price on tie rod replacements. very critical parts.
while there are other things that can cause the shimmying, shaking in the front end and pulling to one side, worn tie rods are definatly one of the causes.
once that gets done, have the wheels rebalanced.
with new tie rods, newly balanced wheels and new tie rods you should be good to go.
one other thing to be looking at and they probably already did that and if it was a problem they would have told you about it, is ball joints.
ball joints are a biggie, taking much time to replace and therefore are extremely expensive.
for everyone reading this, for a vehicle purchase i consider bad ball joints a deal killer.
too much money to pour into a vehicle you probably just barely had the money to buy to begin with.
for instance i have a 2001 dodge ram pickup. this is by no means a new truck but ive been quoted from 1150 to 1850 to replace both upper and lower ball joints on both sides and the mechanics time book says its an 8 hour job to replace parts that can be bought for 55 bucks. its gonna be expensive to have done reguardless of the vehicle year. ball joints is just about the hardest thing one can attempt at the shadetree level and very dangerous without the right tools.
i got a year out of the truck before this problem has cropped up.