Laura, you can get a guide to stamp collecting and a free catalog from
http://www.kenmorestamps.com
The best catalog at this time is from Mystic.
http://www. mysticstamps.com
There is a lot of info at
http://www.linns.com
The catalog will give you the prices. The guide has a lof of usefull info much like what you will find at linns site but more and if you got the guide you wouldn't have to keep going back to the web site to find an answer to your question.
I collected full sheets of stamps which I bought at the PO on the date of issue. I put saran wrap around the sheets to protect them. These days you can buy something to put them in.
Sometimes I did just get a corner.
I also bought books because sometimes the stamps were different than sheet stamps.
Always use a tweasers to handle mint stamps.
You can get supplies like stamp hinges and corner mounts from any of those sites also. for single stamps to put in albums.
I sold my collection to a stamp dealer in Wis Rapids, WI.