there are so many diffrent scopes wether it be hawke,bushell,leupeald or nikko sterling some £50 some £500 do you need a £300 scope for a air rifle or will a £50 hawke sport do the job if sighted in propely or is it a bad quality and do i need to change it why does the price vary so much please any tips on sights please and any tips on sighting it in please