Online shopping in Portugal

This is actually one of the most difficult things about living in Portugal.
Banks standardly do not issue debit cards which can be used online. As a result you need to get a prepaid card or a credit card, which can be a pain, especially as when you arrive in the country you have no domestic credit history or proof of prior years' earnings.

The knock on effect from this is no coverage by Amazon, unthinkable in the modern world, and the offering by domestic companies is also extremely poor. Fnac, the French firm, are pretty much useless and embarrassingly expensive, as well as often taking up to two weeks to process simple requests such as reserving a book online for collection in store.
Books are routinely between fifteen and twenty euros, consumer electronics are hugely overpriced due to no online competition for the three large retail stores here, who clearly collude to fix prices with impunity.
I usually buy from abroad whenever possible.

The Spanish Amazon site will deliver to Portugal

That's true, as will the France, Germany and other sites. But they always charge for delivery, increasing prices a lot.

Regarding shipping to Portugal is one matter, but shipping to Azores is another matter. I was buying exotic plants from a nursery online in the Canary islands. One shipment came with most palms crooked in bad shape, so I asked them advise and they advised those will straighten up on themselves and I said OK. After a year I made another order but they ignore me. They do reply to other new customers though. Such treatment of customers is unacceptable but it is their right of course. Just because I ask and report a problem he does not ship his plants to me anymore, this is so dumb practice.

It is not easy to get stuff shipped to Azores, even from Portugal. A lot of businesses would say we do not ship to Portugal and a lot of businesses in Portugal or Spain etc. would say we do not ship to islands. They're just lazy.

ASOS delivers clothes free to Portugal with free returns too. You can pay with paypal. It has some good deals. Haven't found a good substitute for Amazon. But there are companies in the UK that do weekly trips to Portugal and you can pay to get your Amazon products delivered to them, then they drive it over.