Code by JellyPies#8181 - Tue Aug 13 2019 02:09:55 GMT+0000 (Coordinated Universal Time)

CodeBlockPaste.c++

// LCD Start
#include <LiquidCrystal.h>

const byte rs = 12,
           en = 11,
           d4 = 5,
           d5 = 4,
           d6 = 6,
           d7 = 7;
LiquidCrystal lcd(rs, en, d4, d5, d6, d7);
const byte screenWidth = 16;
const byte screenHeight = 2;
// LCD End

// Coin Accepter Start
float balance = 0;
int acceptorPin = 2;
// Coin Accepter End

void setup() {
  // Runs 1x
  Serial.begin(9600);
  lcd.begin(screenWidth, screenHeight);
  pinMode(acceptorPin, INPUT_PULLUP);
  attachInterrupt(digitalPinToInterrupt(acceptorPin), addBalance, RISING);
  initializeSystem();
}

void loop() {
  // Runs constantly
}

void addBalance() {
  balance += 0.25;
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Balance: $");
  lcd.print(balance);

  if (balance >= 1.00) {
    lcd.setCursor(0, 2);
    lcd.print("Select Item");
  }
}

void initializeSystem() {
  balance = 0;
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("    Welcome!");
  lcd.setCursor(0, 2);
  lcd.print("  Insert Coins");
}