Firewalls

How many times you wonder should I use a firewall or what are the chances of me getting hacked? and I don't feel like paying for a software program.

Most of you know what firewall is and what it is for.
Here is a bit more information.
A firewall is an information technology (IT) security device which is configured to permit, deny or proxy data connections set and configured by the organization's security policy. Firewalls can either be hardware and/or software based.
A firewall's basic task is to control traffic between computer networks with different zones of trust. Typical examples are the Internet which is a zone with no trust and an internal network which is (and should be) a zone with high trust. The ultimate goal is to provide controlled interfaces between zones of differing trust levels through the enforcement of a security policy and connectivity model based on the least privilege principle and separation of duties.
A firewall is also called a Border Protection Device (BPD) in certain military contexts where a firewall separates networks by creating perimeter networks in a Demilitarized zone (DMZ). In a BSD context they are also known as a packet filter. A firewall's function is analogous to firewalls in building construction.
Proper configuration of firewalls demands skill from the firewall administrator. It requires considerable understanding of network protocols and of computer security. Small mistakes can render a firewall worthless as a security tool. [credit goes to wikipedia]

anyways I found a bit of free firewalls so that you don't have to pay for the expensive ones and it works the same.

http://www.personalfirewall.comodo.com/ COMODO
http://www.zonelabs.com/zap26_za_grid.html zonealarm
http://www.agnitum.com/products/outpostfree/download.php Agnitum
http://www.sunbelt-software.com/Kerio-Download.cfm Kerio

Comodo is rated the best.

Now I can't tell you what are the chances of getting hacked, but isn't it much better to be safe than sorry?
I personally don't use it, but thats because i know how to keep my information safe and also I am behind a router (linksys)
if you are behind a router, check if it has a built in firewall.
I definitely recommend linksys products.
http://www.pcmag.com/category2/0,1874,1055304,00.asp
there a link for you to check out what you can buy for firewall machine.
You don't need to download just have it as if it was a router itself.