Need new air filter
 

from what ive read the Mann ones are pretty well regarded, so are they about the best ones to go for without paying crazy money?

anyone suggest where is a good place to order them from?

Lots of places sell them, just Google and see where is cheapest.
Be careful with eBay, unless it's a proper business seller you may not get a genuine part.
Mann are good as are Meyle and Bosch.

Consider also, Mahle.
They make some of the genuine Volvo filters.

I use a K&N one now. Before that any Bosch, Mahle, Meyle one was fine.

Mann and MAHLE are both OE suppliers to Volvo, and purveyors of quality parts. A lot of counterfeit parts about though, so worth avoiding cheap ebay sellers.