I have a Deluxe Sporter, and I put a Tasco 3-7 X 20 rimfire scope on it, about $20.
http://www.tasco.com/products/index.cfm?ClassID=13&FamilyID=167&ProductID=691
I did use a Weaver T-09 mount instead of the Ruger mount. The T-09 is thinner, and I can still use the iron sights without removing the scope. And I replaced all the scope's screws with stainless hex head ones (comes with Phillips head). The mount and screws were like $9.
The scope surprised me. It's amazingly good for twenty bucks. It is bright enough even on a cloudy day down to dusk. It has a square view, plain reticles, and positive 1/4 MOA clicks. It holds zero most times when I remove it for cleaning the gun. One time it did get off a click to one side.
It looks good on the small 10/22, proportioned. Larger scopes just look clunky and top-heavy to me.
An old post of it on GunTalk:
http://www.guntalk-online.com/forum/viewtopic.php?t=1996&highlight=tasco