Standing above the clouds at Machu Picchu at sunrise is the kind of travel moment that stays with you forever. You want to aim for the dry season between May and September to actually see the ruins without them being socked in by rain and fog.
A typical trip runs about $4000 once you factor in flights, trains, and entry permits. Spreading that out over time helps keep the cash flow steady while you lock in your dates.
The 0% intro window is a deadline, not free money. If you still have a balance left when those 18 months are up, standard interest kicks in on what is left over.