One of the most important parts of coin collecting is to organize, catalog, and inventory your collection. This is important for you, so you know what your investment is, what you have, what you still need, etc. This is also important for later in life, when your collection is inherited by another family member. Chances are, the person inheriting the collection is not going to know much, if anything, about numismatics and may think that you were just "some old person with mental problems who put useless coins in a safe." No, I am not suggesting that older people have mental problems. I am only suggesting that that may be what some people think when inheriting a collection, since they know nothing about it. The person inheriting the collection may end up taking the coins to the bank, or maybe to a pawn shop, or a thrift store, or maybe they know enough to at least take it to a coin dealer. If you have cataloged and inventoried your collection properly, others will have little problem finding out what the coin is, how much it's worth, etc. Most of the time, a catalog includes the following information about each coin: Year, Mint Mark, Type, Grade, Purchase Price, Purchase Date, and sometimes, Estimated Value. Here are the different ways to go about this. 

1.) Cheap Notebook 

One of the cheapest ways to catalog a collection is to use a simple notebook, which can be had for under $1 at many stores! You can track as much, or as little information as you'd like in whatever way you want. If you have a small collection, this may be perfect. While the notebook route is great (and that's what I started out with), once a collection grows, it becomes much more difficult to handle and doing it by hand makes it almost impossible to reorganize or rearrange your catalog if necessary. 

Notebook: https://www.kmart.com/studio-c-47172-hair-of-a-dog-personal/p-SPM9151911702 

2.) Spreadsheet 

If you use Microsoft Excel or Google Sheets for work, you are probably very familiar with spreadsheets. They can be made as long as you want and are easy to edit, sort, and organize to fit any new coins with ease. You're not limited in what you can keep track of and you can often even include pictures, but spreadsheets are generally used only for information. You can even create different tabs for your different sets of coins. As an example, you could have a tab with your "Franklin Half Dollars" and another with your "Morgan Silver Dollars." There are also free alternatives, like OpenOffice and LibreOffice. Once I discovered the notebook didn't work well for my collection, I switched to the Excel route temporarily. (Yes, I've used all these different forms of cataloging). 

Microsoft Excel: https://products.office.com/en-us/excel 

3.) Checklist 

A checklist can go along with any other type of cataloging, whether it be a notebook, spreadsheet, software, etc. Checklists are great to see what you have and what you still need, but unfortunately, do not generally have options for purchase date, purchase price, grade, and other more specific information. You can make your own checklist easily on a piece of paper or in your notebook, but there is also a book specifically related to check listing, The Official Red Book: Checklist and Record Book of United States and Canadian Coins. 

Checklist and Record Book: https://www.barnesandnoble.com/w/checklist-and-record-book-of-united-states-and-canadian-coins-whitman-publishing/1121777580 

4.) Software 

This is where you have loads of options, choices, etc. There are many different pieces of software you can use for cataloging your collection, so you should find what fits you best. There are paid (and open source) options that are made specifically for coin collections, such as Collector's Assistant and OpenNumismat, that are both available for the computer. If you want something more mobile or online based, again, you have options. You can go with a mobile app, like US Coin Plus, which is an app I used to use. Other great options include the PCGS Set Registry, which you can actually use to catalog any coin, regardless of it being graded by PCGS. An option that is less conventional, but one that I like nonetheless, is social media cataloging, which is what I switched to and probably will stay with. Snupps is a great application for collectors of anything and is a very convenient way to catalog your collection. If you don't want other people snooping around your collection, you can set your account to Private. This option is great because you can have all the data about your collection in one app. This way, if you're at a show or a dealer, you can open the app to see exactly what you have and what you need. One of the best options with software is that many can be used wherever you are and you can insert pictures, something you cannot reasonably do with a notebook. 

Snupps: https://www.snupps.com/