Last box of cat5 cable I bought was about �100 for 300 feet (i think). Screwfix probably sell the tools (B&Q do too).
A set of back boxes \ modules should cost no more than 20 quid.
I was given my Krone tool by our data cable contractor, but Maplis have these for about �15 I'd think.
If you want to put plugs on the ends - a cheap crimper will probably do the job, but I ended up replacing my cheapo for an expensive one after about 6 months of light use (it's still going strong and cost about �80 5 years ago). Biggest outlay by far will be the cable.
ps - cant you borrow the tools from work? (after all, you do work for a teleco
).