Your best bet is a set of headphones. Forget the headset. Hit your local music store such as Long and McQuade in Canada and see what they have. Get something with a removable cable so when it breaks just buy a standard 3.5mm cable and replace it in 2 seconds. Otherwise you have to open the headphones and solder on a new cable.
Anything from Grado, Shure, AKG, Seinheisser, Audio Technica, etc... They are all good. You can find something under $100 easy and if you have a Long and Mcquade they have great prices. For example with a Seinheiser in the future if the ear pads get worn out you can get replacements easy. You can rebuild them all with parts and the headphones can literally last forever. A headset is lucky to last 2 years.
Now to power the headphones just use your computer for now. So if you don't have a headphone amp onboard, or on a soundcard, or you don't have a USB DAC, then look for headphones with low impedance and high sensitivity. The onboard sound will drive those no problem. If you have a headphone amp then no problem. Don't worry too much about sound quality at the $100 range. Look for comfort and a removable 3.5mm cable. AKG are very nice, but they use a mini XLR cable so it's harder to find and bit more expensive to replace. I use AKG though and love them. If I need a cable I just order one for $30 instead of an el cheapo $10 3.5mm one.
For the mic you have 3 options. A mic built into a webcam if you have one. If not and you want a webcam, good time to buy one
. Otherwise a USB mic for $20 or so will work. If you want a very good mic a Samson C01U or Blue Snowball are 2 of the best USB mics for PC. More expensive ones have different pickup patterns which are not required for straight chatting with PC use. So you don't need them. The 2 I listed will work great and are $50 each. You can buy them at Best Buy and they often go on sale.
So the $100 headphones, and the $50 mic will be a great combo. In the future you could get a $25 shockmount for the microphone, and a $25 desk arm to mount the mic so you can move it around like a radio station. Then you can position the mic from your mouth for thebest sound and to eliminate it picking up keyboard noise. For the headphones you could get a USB DAC to improve the sound quality to pro level. No need for onboard sound or a soundcard.
Just to help. If you go looking at headphones you'll notice 2 styles. Open back and closed back. Open back allows you to hear the environment, so if someone is yelling at you hear them, or the telephone, or door bell. But others hear your headphones. Not good for an office or airplane. Closed back seal out the noise so you don't hear anything and others don't hear you. I love my open backs cause I can converse with my wife with them on but the only downfall is if she's watching TV it bothers me while gaming since I hear the TV. Open back is supposed to produce better bass but at $100 don't get too picky. It's not like a $500 pair where you get a bit more choosey. You'll notice a lot of headphones labeled as DJ. These allow you to flip one ear pad up so you can hear the crowd. Not desired for home use. Thought I'd mention it since some people think DJ headphones are professional so better quality or sound better. It's not the case at all it's only about the hinge to flip the earpad up.