im incredibly cheap, but i still haven't truly made a beer just to make a bunch of alcohol. ie. 75% plain 2row/pils (whatever's cheapest), $4 dry yeast, 25% white sugar 1.045 OG, 1oz of $2 high AA hops - likely ending up at a 5.5% ABV beer for ~$15 for 20 litres of beer.
if $15 for 20 litres of beer is out of your price range, idk what to say.