Battery Replacment on my ford escort lx sedan

so i got a ford escort lx sedan from my fathers roomate, he said he never had an
owners manual and the car's battery needs to be replaced, and apperently it needs an
axel check, i dont know that much about cars and ive asked around but im not sure
were to get a new battery for it since i cant take it anywere to have it looked at. i work
days and nights so i dont have the time or money to have it towed and i dont want to
spend too much money on getting a new battery for it. i have no clue what kind of
battery to get or if theirs a certain size, fit or type of battery to get and i was hoping
you guys could help me out  :}