Buy different blank color dice. Each color represents a specific kind of unit.
http://www.dicegamedepot.com/blank-dice-3/
Buy stickers for the dice. Put a sticker on one of the sides of the dice. This represents a att/def value of one. Add one sticker per side for different att/def values.
https://www.amazon.com/dp/B01CQ1DWAK/ref=asc_df_B01CQ1DWAK5249144/?tag=hyprod-20&creative=395033&creativeASIN=B01CQ1DWAK&linkCode=df0&hvadid=167135337582&hvpos=1o4&hvnetw=g&hvrand=446623929194174859&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9017490&hvtargid=pla-313521265653