Control arm bush.......

[ainarssems]

If you can do the job yourself it might be worth it. But if you have to pay somebody for the job then it is probably false economy as ball joint might be failing soon as well on the arm. If it's just creaking without excessive movement I would be tempted to spray some PTFE lubricant in it to silence. If it's worn and need replacing then I would be looking at replacing complete set of arms especially if paying someone else to do it.

Bushes can be changed but you will need a press and arm needs to be heated to expand and release the bush.

If you need to pay £50 for the arm, £50 for the labour and £30-200 for wheel alignment (depending where you go and how much done) the only saving you can make is £35 if you get £15 bush instead of £50 arm which is not a lot if you consider risk of doing all again at full price 6 months later because the ball joint fails. In another country where parts prices are the same but labour costs much lower it could make more sense.