You would probably be able to get even cheaper used routers at a garage sale or at a thrift store. You should be able to pick up an older used WiFi router for $10-$15 bucks. Actually...I was just at a local electronics store...and they were selling a new router for $24 bucks.

One thing to be careful of...since you have some older Mac's in your collection...is make sure that the WiFi router you get is wireless "b" compatible. Most older routers you will come across will be wireless b/g compatible. I think some newer routers (that are wireless "n" compatible)...are only g/n...and no wireless "b".

Also be aware that if you wanted your iMac G3 to be capable of wireless networking...you need a special adapter for the airport card.

As far as how to install the router. Wait until you actually find a router & purchase it. If you don't get install instructions with it...then you can go online to most manufacturer websites & download the install instructions.

Hope this helps,

- Nick