Buy bulk from Monoprice. 1000 feet for less than $100 + shipping. The other parts are dirt cheap, a buck a faceplate. If you are only using face plates then you don't need cables or crimpers. Can probably find someone who is willing to split the cost of the cable so they can do their own place, or just sell the excess on Kijijiji afterwards. If you are not comfortable crimping your own cables, or putting in the faceplates, you could probably work out a deal to trade excess material with someone who is able to do it.
Might as well get Cat 5e or 6 in case you ever want to go over 100Mb/s. Make sure it is in-wall rated.
Cat 5e
Cat 6
Crimpers
RJ45 connectors
Single Faceplates
Double Faceplates