Hi Chicci and welcome aboard
When you say a TV monitor I assume that you mean a normal TV ?
I assume that you are one of our american cousins seeing as you want it for under $100 not £s
You will need a graphic card with TV out,(preferably an AGP one if your PC has an AGP slot or a PCI if it hasnt got an AGP slot)I recently bought one in the UK for £49,128mb DDR Geforce 4 MX 440 SE AGP,(but there are some even cheaper) and from what I have seen when comparing USA prices to UK prices things seem to be the same price to you in dollars as they are to us in pounds sterling
To connect the TV out from the card to a TV I have used a S-VHS lead to S-VHS lead(sometines called S-VID).
You will then need another lead for the audio from the PC to the TV,this will go from your soundcard (onboard or a PCI one),as a 3.5mm stereo jack plug to two phono plugs,via the LINE OUT socket,( I believe that you call them RCA plugs in the good ol' US of A ).
Depending on the distance of your PC from the TV the price will vary a little for the leads but they arent expensive.
I bought a 10 metre high quality S-VHS lead last week for under £10 (I did have a cheaper one already which cost £2 but I want to run it under the floor of my house so I wanted to use a better quality lead hoping that it will last longer).
I hope that this has answered your question,if there is anything that you are unsure about get back to me and I will see if I can clarify it for you