After 10yrs, the suspension on my 98 (4runner) was pretty much shot. Michigan winters are not very friendly to cars.
When i jacked the rear up to rotate the tires, i saw something fall. upon insepction, i found that the top bolt holding the shock onto the frame had rusted off. I changed the rear shocks that weekend.
I left the front end, a while longer, until I found that the vehicle handles like crap (vs our other rides). When I took off the driver side wheel, found that the tie-rod had rusted and broke off - there was nothing holding the sway bar.
Several years ago, had a friend with a 2nd gen Integra. she took it in to acura to have them tell her what needs to be repaired. one of the things they recommended was the struts (i repaired everything else - rotors, filters, tires, muffler, etc. )
if she was to keep it, my suggestion was also to change the suspension. it handled like a turd, but due to funding issues, she did/could not. several years later, she finally bought a new car (vibe), and gave her car to a friend.
her friend also never changed the suspension. it got her from point a to b, until 2 or 3 accidents later when the vehicle was totalled.
so, whether you change the suspension or not is ultimately up to you.
if the vehicle has more than 50k, you should feel a great improvement to your ride.
As for pricing,
To have a shop do it, that sounds "normal".
I did mine myself. it was around
$80-100/corner for each shock/strut,
$70 for the tie-rod,
$40 for a top plate (mount?) - only needed one,
$20 for some saw blade/dremmel bits to cut off the rusted parts, &
3hrs crawling under the vehicle.
(i already had a spring compressor)