The cost will vary depending on the type of equipment you choose to purchase for your setup. If you know a bit about computers and understand connections etc you can probably do it. One of the most important points is to make your setup secure so that it is not open for others to see and get on. Here is a pretty good guide, if you do some google searches there is a wealth of info on this topic and on the equipment to use. For wireless I suggest always going with the newest technology available it will be more secure. And here is the guide by microsoft. http://www.microsoft.com/athome/moredone/wirelesssetup.mspx http://www.microsoft.com/windowsxp/using/networking/learnmore/bowman_05june13.mspx this one has pictures of components http://www.pcstats.com/articleview.cfm?articleID=1428 when you are considering your components do searches for them on a site like newegg.com, there you can read the specs for the item and also a list of comments about that item by actual owners. Here is a link that might be useful: guide

I also got a netbook for use when traveling, my choice was to get the ATT air card for mine that way no matter where I am I can use the air card to connect. It is secure and I am the only one using it. When at home I can either plug directly into my router with an ethernet cable or use my air card until I move to a wireless router in the future. I had my cell phones with ATT anyway so I went with them but there are other companies that have air cards such as Verizon and Sprint, I did comparisons and the ATT and Verizon seemed the best and both are about the same price, there is a cost for the card but they had a rebate that paid fully for the card, I have a monthly fee for the card just like if it was a cell phone and in fact it does assign it a cell phone number. so anywhere you would have cell phone coverage you would be able to use it. I have not been anywhere yet that I did not get a signal. For the price they want to charge you for that one week you could pay for your air card for a month.

WiFi is a standard written by the 802.11 committee of the IEEE. Yes, IEEE screwed up in not getting their name more visible in the marketing side of the technology. It is now a number, 3 or 4 I think, standards for wireless digital communications over relatively short distances. The only applications I am aware of is for connecting computers to the Internet. My notebook, and all newer notebooks to my knowledge, come with one or more versions of WiFi (IEEE 802.11x) built in and ready to connect.

That is an old thermostat. I have never seen a thermostat with soldered connections! Is the HVAC system the same age as the thermostat? If it is I would love to see pictures of that too. If you have heating and cooling, and you can control the fan, then you need at least 4 wires (Power, heating, cooling, and fan). If you have independent transformers for heating and cooling, then you need two power connections which makes 5 wires. It is difficult to tell how this thermostat is connected. Do you have any documentation? Can you trace the wires back to the furnace and AC? At the very least you will have to figure out the function of each wire. See if the terminals are marked at either end. I don't think the color of the wire is going to help. Most WiFi thermostats required a ground connection. I can't tell if this thermostat has one or not. I am not aware of any WiFi thermostats selling for $100.