Look it up on the internet, For "brand new" It depends on what size, manufacturer you choose, tyre size, tyre manufacturer. 17" alloys with tyres in the UK range from £750 up to £4000 ($1200 - $7000) decide what "you" can afford and then look for a set up to match that.
For the Ebay option around £400 ($700) for a set of 4 alloys with tyres. But like I said before, you can plan on spending what you can afford to spend. set a budget and stick to it.