Everyone does catamaran party boats to isla mujeres for like $80 but honestly the regular ferry is SO much better

Ultramar ferry from puerto juarez only 200 pesos round trip (like $11) runs every 30 minutes. Takes 20 minutes and you see the actual water instead of being trapped on booze cruise with drunk spring breakers

Once there rent golf cart 400-500 pesos for day and explore whole island. Playa norte is gorgeous and free, underwater sculpture museum is wild if you snorkel, food way cheaper than cancun

Pro tip: weekdays if possible. Weekends are crazy with locals from cancun too. Bring cash most places dont take cards