Oil changes is the easiest thing you can do for preventive maintenance on your car..
Jack up car, put on jackstands
find oil drain plug, 14mm for most Toyotas, 17mm for most Hondas, loosen completely
let oil drain in oil pan catch
locate obvious oil filter and remove
replace with oil filter with slight grease around the lip of the filter
install
put oil drain plug back in
fill up with oil
thats it.. supplies run about $12/$13 for the oil and filter... and they charge you at least $20 or more...