As stated, wireless router £50ish,


And each wireless card will cost what (considering than many MB /
systems now come with a RJ45 port as standard ?...

Also what if the OP then finds that there are problems with wireless
coverage (not to mention the added security risks of wireless), hard
wired Cat 5 network is 99 percent certain to work first time and don't
have half the security issues that wireless network does.....

Security is not an issue if you read the manual ;-)

Network cards - should be no more than £20 inc vat tops.