 
 <prompt> Joe pizzeria get beta promo. If you buy any regular large pizza, you fit buy di next 3 medium pizzas for $5 each. Wetin be your total savings if di regular medium pizza price na $18 and you use di promo well well? <response>: If one medium pizza cost $18 and with the promotion I fit buy one for $5, then I dey save $18-$5 = $13 on top each medium pizza
If I use the promotion well well, that one mean say I buy all 3 medium pizzas, so I save total of 3*$13 = $39 in total

The final answer: 39. 