FREE WIFI
The easiest alternative is to go to a bar or public place with free internet access.
Since the advent of WhatsApp you can get free wifi in almost all cafe bars and restaurants.
Remember that it might be a good idea to use a VPN if you are using your credit card on a public network.
Hotels and apartments usually have good free wifi.
ESIM
What Is an eSIM?
An eSIM is an embedded SIM card that is built directly into a mobile device's hardware. Unlike a traditional SIM card, which is a physical chip that needs to be inserted into a device, an eSIM is a virtual SIM that can be activated remotely by a mobile carrier. This eliminates the need for swapping physical SIM cards when changing carriers or traveling internationally.
Buy a Spanish Pay as you Go Sim
Go into a shop of one of the Spanish phone operators and buy a sim. The pay as you use without a contract is called "pre pago". Some of the companies will even send a sim through the post. There is a list of Spanish mobile operators here
Click on the links to see the most popular activities that you can do in these places:
Note that the booking system uses a Spanish system and there is no involvement of any American company and no US tariffs.