Best left to a gunsmith.
Cabela's has them.
You should be able to find some of the resellers of ruger 10-22 magazines online at popular sites like ebay.
5 and 10 shot
Yes, there are a variety of magazines for the Ruger 10/22. I have seen them advertised that hold up to 50 22LR bullets each. There are also magazines that hold 20 or 30. The standard magazine holds 10. If you use "magazine" rather than "clip" you will get better results in your searches.
50-225 usd
10-200 usd
Try Midway.com. However, some states do not allow more then 10 round magazines
Well yes, I would
The receiver is not interchangeable nor are the forearm or the stock. The barrel and magazines are completely interchangeable I use 10/22 mags and a 10/22 fluted bull barrel on mine.
10-200 usd
10-500 USD or so depending on the specifics.
Contact Ruger