Hey im 18 and joined the army as infantry hop efully airborne. i was just thinking about my future?

i joined for the love of my country and to help out anyway i could but i was curious how much do most people end up with after 4 years in the army as around E4 or E5. im plan to stay in the barracks.i guess my question is how much money do you spend on fun stuff outside of base? i plan to put a down payment on a cheep house when i get out. i guess thats why im curious to know