@Ryan Morris first of all sorry for the late reply, I don't know why I never came back to this thread until now because @Mark C. identified me, so thank you Mark!
I'm located in Lisbon but I like Porto, there are good fundamentals there. The cost per unit will vary greatly depending on if you are talking about getting one single unit or getting a multifamily property and the type of neighbourhood you want to be in. I would like to add that like @Mark C. said there is no MLS and the price a property sold for is not public, which makes running comps a little bit different since you can only see listed prices and not sold prices.
Not going too in-depth the gist is the rental market is becoming stronger but beware that the prices being practised right now, especially in Lisbon and Porto, are due to lack of supply and are starting to be too high for Portuguese people (couples can afford if both are working but usually they will have 40-50% of income going to rent, if it's one single person they will need to have roommates) and new construction is peaking up so beware on the underwriting. Also, Portugal is a country of buyers, not renters, things might be changing within the younger population but it becomes hard to justify rent if the mortgage instalment would be significantly lower than the rent due to the low-interest rates and "cheap" new construction (the feasibility of these projects was underwritten at the market value of 3-5 years ago, which was lower).
That being said you can find very interesting deals if you know how and where to look, don't be afraid of putting an offer in even if it's low! I have a friend (investor) that after running his numbers puts in an offer, usually about, 50% below asking price, also I know of an agent that represented a lady buying an apartment in Porto listed for 1.000.000€ for 400.000€, most listed prices are wishes not representations of the market, don't let them fool you!
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Now going into @Mark C.,
If you do your underwriting correct and are able to negotiate the price down, the bank appraisal shouldn't be an issue, even if you have to pay for 2 or 3 of them (met an agent the other day and he told that recently he was selling an apartment here in Lisbon for 250.000€, first appraisal was 180.000€, they ordered a new one, second one came 220.000€, they ordered a third one and that came 250.000€), banks are sitting on cash they need to lend, they are extremely liquid at the moment, the key for appraisals is learning how they do it and helping them (read, do it for them), have someone there (you or the agent), talk with the appraiser, explain what you need, show/give him the comps and how yours differentiates. Keep in mind that although you pay around 250€ per appraisal, the bank hires a company that hires the appraiser and he makes significantly less, they are not going to waste too much time on the report and I understand, for that money, I wouldn't either.
I don't know the specific cases you are talking about but 50% LTV is more or less guaranteed for a foreigner to get as long as they show some income, so I understand that whoever they spoke with just gave them that (most managers and salespeople within the banks are not used to foreign clients so they don't even know what to ask for in order to give the financial or risk department more assurance), but it's possible to get more, I have a friend from the US that got a loan under personal name for investment (not for his primary residence) at a little bit over 60% LTV without being a resident here. In this case, they need to try and find a mortgage broker or a banker that is familiar with the process, I would go for the mortgage broker so you are not tied to only one bank, besides, the broker only gets paid if the deal closes (so they have an invested interest) and is the bank that pays him/her, not the client.
I like your strategy, were you thinking about keeping the property and just keep "collecting" them or sell it and move on?
I like both https://www.idealista.pt/ and https://www.imovirtual.com/, but I use them as a starting point, I very rarely contact anyone through it due to the high no-reply/slow-reply rates.
Please take everything I said with a grain of salt, it's my opinion (don't sue me bro!), that being said I'll check this more often, if you need anything just reach out!
Almost forgot my little plug -> I'm a mortgage broker here in Portugal