Welcome! I'm glad you are having fun with your first roll. Here's some advice I'd give as an experienced collector (though nowhere near the level of expert as some people here).
Buy the latest
RedBook. That is practically a requirement for the library of any coin collector. It is a widely respected guide that will give you the current retail value of pretty much every US coin. In fact, I'd suggest getting the "Mega
RedBook". It is huge, but it has a wealth of information beyond the normal version of the book. I hadn't bought a
RedBook in years and it was time for a new one. When I saw that one I bought it right away. It is huge though! Don't blindly trust that the value you see in the
RedBook is what you will get. It is an approximation. The way I like to use it is to quickly see what the valuable dates in a series are. For example, if I see a series averages $20 for a particular grade, but a certain date and mint mark
is $100, I know that is a key date worth remembering as the relative value is accurate even if the exact value can vary a bit.
The coin grading guide is also very important. There are several out there but if I were you I'd take up Slider23 on his offer.
I'm guessing you bought that roll on
ebay. Most of those rolls were put together by the seller and made to look like they are old. He'll put in just a enough interesting (but not especially valuable) coins to make new collectors happy, but don't expect any big finds. True roll hunting is going to the bank, getting rolls, going through literally thousands of coins to find a few interesting ones. It is a lot of work for what you get but it is essentially free so long as you have money to buy the first rolls as you just keep exchanging them when you are through. One of the best things you can do is join your local coin club (if one is in your area). That's how I started when I was a kid. Got a lot of great coins for good prices and the people in those kind of clubs usually like helping out new collectors.
You can find interesting coin bargains on
ebay, but it takes effort and experience. I can often get low to mid grade coins for 1/3-1/2 their actual value, but it takes some skill and the willingness to lose money on a bad pick from time to time. Get good at grading before you do that. In fact, I'd be careful about buying any coins on
ebay that aren't graded by one of the big 3 grading companies until you start feeling comfortable with grading.
Finally, in terms of grading don't get caught up in all the numbers just yet. Someone explained the various AU grades above, which is good. But to start just worry about being able to tell a coin belongs in the AU category vs. the EF (also called XF) category. Basically learn to grade a coin to a basic AG, G, F, VF, EF, AU, or MS grade. Once you can do that fairly easily then worry about the sub-grade within those categories.
By the way, I got fooled by a coated steel Lincoln once. Later I bought a high quality untampered one. If I remember later I'll post a picture of the two side by side. Maybe it will help you tell the difference.