The date of manufacture is listed on the sidewall of the tire although it is a code number not just a date. The date of manufacture can be found in the Tire Identification Number or sometimes call the tire Serial #. On the sidewall you will see DOT followed by a series of letters and numbers. The last 4 numbers are the date of manufacture. The first 2 of the last 4 are the week of manufacture and the last 2 of those 4 are the year. An example is DOT U2LL LMLR2310. In this example the last 4 numbers are 2310. That shows you the tire was made the 23rd week of 2010.
The place you buy a new tire will dispose of the old tire for free.
Take your car or old tire to a tire store. The employees there will be able to determine your tire size needs and recommend a good choice for your vehicle.
You will probably want to buy tire from Bell Tire if you look at their website you will see that their tires are cheap. Then you can locate a store near you.
Walmart and sears sells spare tire covers. You can also find some online from amazon or ebay.
General Tire is actually a specific brand of tire. You can buy their tires directly off their website. Here it is: http://www.generaltire.com/ Most major tire retailers will carry the General brand of tires. You can even find them at the walmart supercenters in the tire and lube section.
There are many places to find tires online. Some such locations are Discount Tire Direct, Tire buyer, and tire rack. I would suggest first to type tire into your browser then click on whatever is preferred.
E-Bay? Craig's list?
No, you have to buy a wider tire.
You should do what you would want done if it was your car. I would buy a nicer tire than your friend had.
You may be able to find tractor tire tubes online for under $100.00. Chances are that if you check Craigslist you'll be able to find exactly what you are looking for.
You can find radial tires in many different stores like Canadian Tire and also at tire dealerships like BF Goodrich. It is not recommended to buy tires online. It is best to buy tires somewhere where they can be properly put on your vehicle.
Buy a new tire.