Cost for front ball joints on a mk4 Clio?

Spies

I'm told I will need new ball joints soon enough as I'm getting wear on both outer edges of my tyres as there's play in both ball joints. 

I understand that Renault don't sell the rubber parts so it's a whole new lower arm, what would the associated cost be to replace both? 

Goudy

You often pay more in labour if you just replace the bushes and ball joint rather than replacing the whole arm.
Labour pushing out the bushes and ball joints tends to negate any savings over the whole arms.
Only really worth it if you fit polybushes (if they are available).

Price will depend on whether you go for original parts or pattern parts.
A cheap pattern lower wishbone can start from around £40 or so.
A decent, branded pattern £60 upwards.
A genuine Renault part probably double that.

Labour will likely be around 2 hours, perhaps a bit less for both sides to remove and fit.
They are pretty much bolt off and on, though they often need some weight taking off them by compressing the suspension springs.

It's also advisable to get the wheel alignment checked after. In fact I would insist on it.