You can buy EU traveller SIM's that will easily cover all the data you need to use anywhere in the EU, usually they rely on Orange in Spain as the network provider so you're restricted to 3G, and they are the most expensive option but easiest to arrange where you are (Canada).
My preferred option is to simply buy an Orange or Vodafone sim in Spain, I like 4G and Vodafone seem to have great rural 4G coverage so I go with them. In the US / Canada you call them prepay sims, you can buy them from shops in literally every town. You have to present your passport now so they can link it to the SIM incase you are a terrorist, but that takes seconds. You can also top the SIM's up with more prepay cash in literally every bar in every tiny village in the entire country, so it's a super easy option if you run out of call or data time.
When I was staying in Talavera last summer I used about 200 gigs over a month doing online work and streaming movies, music etc and never had any problems with Vodafone. You basically pay 20 Euros or whatever and they give you X minutes and X data, which when you run out you simply pay another 20 Euros in any bar, small store, coffee shop and then get your allowance again, there's no limit to the number of times you can do this.
You don't have to pay 20 Euros you can pay less and you get a lower allowance, there's a step system so 5 Euros might get you a tiny amount, 10 some more, and 20 the max.
Buen Camino, SY
