A new bearing is between £55 - £115 depending on where you buy from and what brand. So they are charging you 2.5 hours labour at £75 ph if they charge you £80 for parts. That is for just the bearing assembly, the hub will need to be pressed out of the old one and into the new one.
For you to do it you either need to buy a press or pay a garage £20-odd to press the hub out & in. Depending on the age of the car (2008 cars are 9 years old now) the bearing assembly could be seized into the knuckle, requiring lots of swearing for many hours with hand tools or a few quick minutes with air tools in a garage.
You will also need to buy tripple square bits to undo the 4 bolts that hold it in and a torque wrench for the hub bolt and a large allen bit socket for the hub bolt, and a breaker bar to undo the hub bolt and a jack & axle stands, etc, etc.
This is on the assumption you have zero tools and equipment already, to you may not need half of that stuff if you already have it.
However my point is, if you've never done it, it will not go easy. I would say the garage prices are fair for the work. Not a rip off but not super cheap "too good to be true" prices either. That quote is just a realistic cost.
However if you want to do it, watch some YouTube videos first to get a good idea as to what is involved and parts can be had from CarParts4Less.co.uk
CarParts4Less are the online only division of EuroCarParts, same stock, same warehouse, different logo and cheaper because they operate online only. They sell 2 versions of the bearing, one for £55, the other for £77.