I've recently got my bike licence and am looking to buy my first bike. The bike will just be used for cheap way of getting me to and from work as the costs to run my V8 everyday is getting out of control. I have no real preference towards high performance, what I am looking for is a bike that will provide me with the best fuel economy. I figured a 250 would be the best option for me because they would be very inexpensive to run, however I live and work in the country and the majority of my riding would be cruising between 90-110kmph. For this type of riding would I be better served opting for a larger capacity bike (say a 500) so my little 250 isn't revving it's nuts off all the time? I know it would depend on a few aspects like engine type and bike weight but generally speaking would one be cheaper than the other or would they both be about the same in the end?