I did an intensive course, cbt, bike hire, and test included for a week for £500, but you'll need your theory test too. Most bike places will do a 2 or 3 day course if you've done riding before, so ask your local bike place for those costs.
My 650, does 180 miles until reserve, for £14 petrol. tyres, depending on your riding, i've had to replace after 12000 miles, but they were old, and had been on the bike for 8 years. (not me storing it) Tyres cost 86 and 125 i think. I get them from Merritts in leatherhead (i think) as they are cheapest.
If your 17 you'll have to restrict the bike too, which'll cost upto £200.
I have just put it through its 15000mile service which cost about £300, for small service (sparks, oil, fluids, and brake pads) i do myself