For BETTER "glassed" scopes there's Mueller APT & AVP(these have A/O), Nikon ProStaff scopes from 2-7x32 all way to 4-12x40, Leupold "Rifleman" 4-12x40 for around that $250 or less range. None of these have A/O and are parallaxed for between 75 to 150yds depending on scope. Found in most WalMarts. These are very good scopes if you plan on zeroing around that 100yd mark. However, I think Adjustable Objective would be a very good for ANY rifle whether they shoot at 100yds or not.
Burris FullfieldII 3-9x40 & Timberland(?) models, a few Leupolds, Redfield Revolution 4-12x40, Vortex models, Pentax, Swift, Nikon Buckmaster 3-9x40, all these scopes can be had for around that $250 or less range, and this is where you really notice the better glass for the scope's cost, and scope's build quality, but most don't have A/O. Redfield has a new model scope lineup called Revelation in 4-12x40A/O, but I understand that it's Chinese, whereas the Revolution lineup is not.
For around $300 there's Weaver V16 "Classic" 4-16x40A/O, Nikon Buckmaster 6-18x40(A/O?), and some Leupold's to choose from.
There's so many scope makes and models out there that it boggles the mind as to what to choose. I own MANY of these scopes I mentioned above and if you want a better scope for less, go for used. Check out Pawn Shops, local Gun Shops, Friends, SWFA(new/used/demo), or any of the Forum's Sponsors' for deals on new. Good Luck on your selection and DO LOTS of COMPARISONS for the features you want/need for the costs involved. Also, be aware, if you go 'USED", the warranty might NOT go with it---so ask. Also some Chinese scopes, do have pretty good glass nowadays, BUT Asian, European, Japanese glass will be much better due to either their glass polishing and coatings on the lens, but other factors of scope should be accounted also. Remember too, that a cheap costing $30 scope might give a lifetime of great service to you, and a $1000 scope might need warranty work the first day of use, and you'll never know until you use it.