I run a small coffee shop and want to offer free wifi to my customers while also having a secure network for my point of sale system/internal network. What is the best way to do this on a limited budget? And what is the best way to protect the secure network?

You can use Web Parts in SharePoint to display information or perform tasks. Before using a Web Part, it must be installed by a SharePoint administrator.If you are interested to find the information about this topic you must have a look at this website you will find all the answers of your question here. Buy Now | HotSpot Software

Just linking a access point or router to your network with a LAN cable will give the customers access to the Internet BUT will also give them access to your local network. (Assuming you have a ADSL Router in place with internet Linked) This is the most inexpensive route.

- A access point is preferred. Connect a LAN cable to the WAN port on it.
- A router will cause IP address conflicts on your network because it also has DHCP. Disable it or connect a LAN cable to the WAN port on if it has on.

A separate ADSL/Internet line is prefigured but more expensive.

Remember to change your password often else people WILL abuse it and bring down your client's speed.

Hope this helps.
Grant