To be honest I don't know what is a standard cost. It has had 10 years of virtually no problems so I expected a bit of expense. Said all the shocks need replacing as need to do in pairs? And front suspension wishbone has more travel than it should. I've used them before and they seem fairly good. I'm hoping that it's general wear and tear and that after this work it'll be good for a few more years.
It's best practice to replace shocks in pairs, but of you're running an older / budget car not absolutely necessary if only one has gone.
Have a look on eBay for your shocks - you'll get new ones much cheaper on there.
With regards to the front suspension wishbone having more travel, that's not a big job either. ( again have a look on Ebay ).
If you can buy all the bits and then go to a garage and ask them to do it for cash, you'll save not only on the bits, but also the Vat too. Any garage will be able to do the work, as it's easy basic stuff, so steer clear of big fancy garages. The inflated hourly rate is to cover the costs of having a big flashy garage, not the quality of the mechanics.
I can guarantee that doing it that way will save you a packet.