Ruger doesn't sell firearms to individuals.
You'll have to purchase one at your local gun shop, sporting goods store, etc.
10/22s are wildly popular, so you shouldn't have any trouble finding them for sale if you have gun shops or sporting goods stores near you.
If you find a particular model you like on Ruger's website but no one nearby has it in stock, often a local shop will order one for you. You may have to pay up front if it's not something they would normally stock.
There are lots of alternatives to a 10/22, but the 10/22 is wildly popular for a reason:
-made in USA
-TONS of aftermarket support for accessories
-easy to work on, especially to swap barrels yourself
-universally recognized- good for resale, or if you need work done on it
If you're interested in reading about 10/22s, check out the forums over at www.rimfirecentral.com/forums
. There's a ton of info there. Be careful that you don't end up spending the rest of your life reading and looking at pictures, not shooting!
You'll find lots of people who spend many hundreds of dollars upgrading their $150-200 10/22. That's fine, but far from necessary for most of us. Putting a quality optic on the rifle, doing some minor trigger improvements (like a drop-in kit from Volquartsen, etc.) and LOTS of practice will make you and your rifle into very fine shooters!
Good luck, and welcome to the Ruger Forum!