The cheapest way to get stains from fabric is to use bar soap and scrub. It will remove "ring around the collar," grease stains, ball point ink stains and a lot more. Wet the fabric, rub the bar soap into it, scrunch the fabric and scrub it against itself hard. It may take a little work, but most of the time it will happen.
(Do NOT dry a stained item in a dryer as the heat will set a lot of stains so they'll never come out.)