building is not so easy well actualy puting a flame to things and brazeing them together is easy a chimp can do it
but the tools almost no one ever wants vac and fill the unit so u will have to do it ur self
to vac u will need a vacuume pump chepest one i found was $80
to fill u wil need gages and a manifold around $30 and up
then the parts atleast 1 schrader valve one filter with a valve on it =$20
condensser =$60
compressor can be pulled from a mini fridge that one can find in the wanted adds for under $50
copper coile =$20 no water line specila stuff
staineless low preshure flex line a trip to home depot it will be in the gas aplice section but u want staineless not aluminum so make shure its staineless so u can braze to it =$30-40
the on die evap u can buy a chilly wich works grate but just the chilly not asembeld yet will set u back around $50 then u ned the rest of the suff to mount in
or u can build ur own but thier is no telling how much thatwill cost u in the end and how much time it will take or u can
buy one of thease that comes will al the clips and crap u just braze in ur low and cap tube and ur set
then the fill gas if u dont have a special paper saying u can buy fill gas then ur stuck useing auto R134a , or R290
so if u have alot of time and want to give it a go why not but it will cost u almost the same to buy one alredy made