Spring in Portugal means mild coastal breezes, quiet streets in Porto, and green vines across the Douro Valley. Booking in late winter gives you the best shot at reasonable flights and open rooms along the coast before summer crowds arrive.
A solid two-week trip usually runs around $3500. Instead of taking that hit all at once, you can break the cost into steady monthly payments and pay it off comfortably over time.
The 0% intro APR for 15 months on purchases and balance transfers is a deadline, not free money. If you still carry a balance when those 15 months end, high standard interest rates will apply to whatever is left.