Sourceforge.net has a tremendous amount of free software. One area they excel at is with web server based software. A web server is a perfect use for an old machine. In fact, I still have an old pII based box that runs our private web server. All the screenshots are from that system. Probably will have to update to a pIII soon.

In any case I found this great piece of software that is easier to install than most desktop applications. It should work on any system with a W/M/Lamp based server (The only real difference I could see was dealing with file permissions). It is a pos or short for point of sale software. This is great for a garage sale or a charity event where you need to sort of act like a small business. Most everything in it is point and click once you have it set up. One thing I like about it is, you can access it with an Ipad, Android, or any tablet that has a built in web browser. That gives you and anyone working with you to have the freedom to move around at your sale and not be stuck behind a register.

Update: corrected a few typos....

Step 1: What's Needed.

Home local area network.
Debian or Ubuntu lamp web server with Phpmyadmin

See: https://www.instructables.com/id/Quicky-web-server-for-linux/

$ sudo apt-get install phpmyladmin

The software from:
http://opensourcepos.sourceforge.net/

Step 2: Set Up the Database.

You will need to decide what names you want to use.

User name: pos
Database name: pos
Database password: thepassword (use something of your own choosing.)
Server: localhost

Be sure to write down what you choose as you will need that information later.

Log into you Phpmyadmin on the web server.

Go to Privileges.
Go down to add new user. click on it.
Fill in the information you decided above. (Do not click on generate password.)
Click: (Create database with same name and grant all privileges)
Do not add global privileges. (for security reasons).
Click go. (You should get a new page saying what was done.)
Click on Privileges again at the top.
Go to the bottom of the new page and click on reload privileges.
Log out.

Step 3: Dns Avoidance.

If you do not want to go to the trouble of setting up a real visible website, then make up a website that does not exist. You can use nslookup to make sure.

$ nslookup myposgarage.com
Server: 192.168.1.1
Address: 192.168.1.1#53

** server can't find myposgarage.com: NXDOMAIN

Then make a virtual site on your server.

https://www.instructables.com/id/Trial-setup-of-virtual-hosts-One-web-server-with/

Note: Be sure to add your new website address to your Local dns server or router.

Step 4: File Maintenance.

1. unzip and upload Open Source Point of Sale files to web server

$ sudo unzip opensource.zip /var/www/
$ cd /var/www/opensourcepos

2. Copy application/config/database.php.tmp to application/config/database.php

$ sudo cp application/config/database.php.tmp application/config/database.php

3. Modify application/config/database.php to connect to your database (from what you used in Phpmyadmin)

$ sudo nano application/config/database.php

4. Modify application/config/config.php encryption key with your own information (optional if on a private network and not using wifi)

5. Rights to files.

$ cd /var/www/
$ sudo chown -R www-data:www-data opensourcepos
$ sudo chmod -R 755 opensourcepos

Step 5: You Should Be in Now.

Go to your point of sale install via the browser (in our case www.myposgarage.com)
LOGIN using
username: admin
password:pointofsale

Tada! You are set up. If you are unsure where to go from here, please consult a business professional about setting up your store.

Web engine search: setting up a point of sale.

If you plan to use wireless, set up the server on a completely separate network besides what you normally use. Use the most complex encryption method you can. Shut down the wireless network when not in use.

https://www.instructables.com/id/Your-personal-intranet-Part-1

Step 6: Need a Little More Horsepower?

If you would like a web interface with a lot more options, you might consider oscommerce. It is also available from sourceforge.net. We als run it on our local server.