Ethernet Cables

I have been using wifi for my desktop computer but I only get a fraction of the internet speed I pay for. I'd like to run an ethernet cable to my computer but the cable needs to be around 150 to 200 feet long due to certain restrictions that I won't go into detail about. Most cables I've found are never longer than 100 feet, and if they are longer the price increases disproportionately. Will a cable of this length give me any signal degradation? Can you recommend a cable of such length? Price isn't really an issue but I'd like to know why the cables I've seen that are long enough to suit my needs are so expensive. Thanks in advance. 

You can run network cable for 100 meters (300ft) before you get signal loss. No idea why they're so expensive. You could always just buy a roll of cable, some connectors and a crimping tool and make your own if it's cheaper.

http://www.ebay.com.au/itm/RJ45-60M-30M-15M-CAT5-CAT5E-200FT-98FT-50FT-Ethernet-LAN-Network-Cable-B20E-/360749526915?pt=LH_DefaultDomain_15&var&hash=item53fe58ef83&_uhb=1

12.95 with free postage