Looking for a reasonably priced set of roof bars that will fit my 2010  Octavia mpi 1.6 petrol  

Is your car car a saloon or estate, and with or without roof rails?

 

Take a look at Thule bars. If you have the factory roof rails then all you need are the cross bars which aren't too crazy in terms of price. 

it is a saloon with no roof rails

like this one

11 hours ago, bigdavestar said:

like this one

 

You'll have to go for the attachments that go under your door frame in that case. Not the most elegant option but it still works. 

I just used cheap bars for my saloon and placed screws where needed to correspond with the fixings at the top of the door frame carried ladders roof box an d all sorts no problem. only fitted when needed.