If you've been enticed to buy a metal detector based on shows like American Digger or whatever it's called with that showman wrestling guy, then I've got bad news for you...Metal detecting is hard work, and you hardly ever find a thing of real value. Even most old coins are pretty much worthless unless you get a key date or something. Most silver coins, for instance, are only worth their scrap weight in silver. I've been detecting for years and have dug my share of old coins and rings. Only 3 of my coins were worth anything worth talking about, and even then we are only talking in the range of $150 to about $1300 depending on which of the three. Far as rings go, most dug turn out to be junk metal, and the gold ones are usually only worth their weight in scrap gold (which is still nice), but then you've got to dig a ton of junk to find those rings, because gold can read like anything on the conductivity scale.
I only mention all this because you seem intent on finding out what you are going to do with all the great finds you make. Not trying to throw cold water on your enthusiasm but if you're in this to find a bunch of valuable stuff then it's going to get old real fast. This hobby is still fantastic though for other reasons. The great friends you meet, the sites you get to enjoy in the great outdoors, reading up on history, and also enjoying the mystery of discovery digging up an old coin or relic and wondering just who touched it last and how it was lost. Far as things worth any real value or where to sell them, that should be the least of your concerns when getting into this hobby. Chances are you'll not have to worry about that for a long time, if ever. Probably the most important thing to know is who will give you the best scrap weight dollar for your gold (which doesn't come easy finding either), and ARA is where it's at for that by most people's opinions.
I wouldn't trade this hobby for any other in the world. The good friends I have for years meeting through this hobby, the sites and history I've learned of, and just a good excuse for getting outside and enjoying a beautiful day. Those are the real riches in this hobby, and I'm sorry to say that all those shows on TV are built on shadows and mirrors that are going to lure a lot of people into buying an expensive machine and finding out that it isn't how it works in the real world. Also, their recovery methods are giving a rather bad reputation to this hobby. In the opening scenes for one thing they are using shovels, and not only that but they are throwing the dirt a mile away from the hole. That alone sends a very bad image to the general public about what our hobby is about. Most of us have very strong ethics about recovery methods and such.
Far as "monetary" value goes, the easiest way to rack up any real dollar amounts is by just going to modern schools and digging clad all day. You can then use that money to buy old coins you want. Silver and other old coins at public sites are hard work and takes a ton of experience to sniff out because of how beaten public venues have been by detectors over the years. Don't get me wrong, that's part of the fun and challenge. If finding silver was easy there wouldn't be any challenge to this "sport". But don't try to cut your teeth on detecting doing it at pounded out old parks. Go to modern parks where you can dig clad and get up to speed faster. Once you've mastered the machine more you can then try your hand at fishing some more old coins out of "dead" old parks. If you try to hit those from the start it will probably quickly destroy your enthusiasm.
Good luck and welcome to this great hobby. Most of us are not going to get rich, but we are going to have a lot of fun trying.
Think I'm finally home after a lot of years searching for my particular needs. Custom 1.5 lb lighter 
Sovereign GT (easy to do by just "building" lighter shaft) & SEF 12x10 as everyday coil. 8" Tornado (actually 7.25") as super heavy trash coil (Very deep & separates better than typical 8/9" true size coils). 13" Ultimate for large fields/beaches on certain days I want to grid faster than even the 12x10's nice improvement over stock for that. Stock 10" Tornado stays on water rig (stock shaft). 
ProPointer. Owned 15x12 & SunRay S-5 (5.5") at one time. Loaned a prior 13" Ultimate & SunRay S-12 (12.5").
Some Oldest Silver- 1835 Bust Dime, 1842 "O" Seated Dime, 1855 Seated Quarter, 1858 3 Cent Piece, 1891 Seated Dime, & another Seated Quarter too damaged to read date. Highest Value- 3 Cent Piece, Seated Quarter, & now 1921 F-12 Standing Liberty. Oldest Coin? Got to give large cents a good look & see. 2013 so far- 1 Seated Quarter, 1 Barber Quarter, 1 Standing Liberty, 2 Washingtons, 1 Barber Dime, 9 Mercs, 3 Rosies. 1 War Nickel. 19 silvers in total, & 1 1872 key date Indian, 2 Bufallos, 1 man's 14K gold medium sized ring & 1 gold chain, with possibility of few 8"+ deep mystery coins being Indians after cleaning.
What matters in life is the journey and not the desitination. How you handle that journey determines if you were a success, not so much what you achieved if and when you finally get there, especially if you made it by stepping on people along the way...
In loving memory of my long haired (wooly) husky Sky. She taught me just how beautiful and pure a soul can be, human or not...
