Thanks for all the help, that sucks because it all sounds really expensive

. And of course I have more questions:
1. Where would I hook the wire/wireless router up to on my modem?
2. Someone told me that GHz was speed, since its not what is?
3. How much do you think it would cost to get everything I need to get the internet to another computer with and without the wire?
4. What are network cards?
This is all way too complicating for me
Im assuming you have Broadband/Cable/DSL, if you have Dialup, than you wont be able to split your internet connection.
1.You would take the ethernet cable that goes from your modem to your pc, and unplug it from the pc, and plug it into the router. You would then have to (if its wired) plug all the other computers into the router with ethernet cables. If its wireless, the router will start sending signal and all the computers with WIFI PCI or USB WIFI Dongles will try and connect to the router automaticaly.
2.In a way GHz is speed, but its WAY to complicated to explain. You dont really need to worry what type of WIFI you get. By type I mean, all WIFI routers are 802.11, but there are different kinds of 802.11's. It doesnt really matter which one you get, because most likly your internet connection is just 1-2MB/s where the slowest version of WIFI is 802.11A-Which runs at 11MB/s, Which is 10 times faster than your internet.
If the store does have a sale going on or something and they offer a different version, 802.11B, 802.11G, 802.11N, you could use any of them. All the difference is they are a little bit faster (there are other differences, but I dont want to bore you), where generaly only busness networks would need that kind of speed (or a homefile sharring network, but we dont need to get into that.)
Besides, if your getting a wired router, NONE of what I said in #2 matters, GHz only has to do with Wireless (WIFI) internet.
3.
I'm going to assume you need a router and to connect to 3 computers, because you never specified in the first place.Well when I set up my wireless internet, the computer store I went to had a sale going on, where you could buy a WIFI Router and get a WIFI PCI Card for half off. So in all my Router was $60, the 3 WIFI cards I bought with it where 15 each. So $105.
I just checked out newegg, and if you want the wireless option, I think this would be some good choices (If you dont mind rebates) They are 802.11G which is faster than 802.11A/B but I dont think Newegg sells anything slower.
Router-$40
PCI card times 3-$60
Going with the wired router, I dont really know how far away your computer is from where the router is, Im going to assume, one computer is right next to the router, and the other two computers are 75 feet away. And I'm going to assume, two of the computers have NIC's (Network Cards, more on this later) built in, and one doesnt. So $90.
Router-$30
NIC-$9
100Ft Cable times 2-$40
10Ft Cable-$9
No affence, but from the fact you dont know much about WIFI, I would go with the WIRED network, its easier to setup.
If you had a WIFI Laptop or something of the sort that already had WIFI built in, then I would go with a WIFI network.
4.Network cards Are just like WIFI PCI Cards, BUT instead of allowing your computer to connect to a WIFI router, Network Cards let your computer connect to a WIRED router. (With an Ethernet Cable.)
WOW, I practicaly wrote a novel. Perhaps I should write a 101 For the networking section.
Anywho, If you have anymore questions feel free to ask.