Pre-cut wire is typically too long or short for your runs, thus
Recommend: 1-2x 1000ft box of cat6
If you want to pull 2 lines at a time it is nice to have 2 boxes to pull from,
if you plan to only pull one line at a time then 1 box works fine.
Calculate the lengths of the runs to get an idea of how many boxes to buy.
Cat 6 Bulk Ethernet Cables - Monoprice.com
you will also need RJ45 connectors and a
crimper
RJ-45 MODULAR PLUGS RJ45 - 100 PACK FOR STRANDED CABLE - Monoprice.com
various prices / models for the crimper tool - the cheapest one got decent reviews, I spent a bit more and got a nicer one which also had good reviews.
Professional Modular Crimps, Strips, & Cuts Tool - Monoprice.com
note monoprice often has discount codes.. such as 15% off with 15SPRING