Questions about working remotely in Greece

Hello.

I work as a freelancer through a co-operative and I'm considering of moving to Greece (namely Thessaloniki as I've spent time there already and got to know the city) for at least a few months, if not half a year to a year to work remotely. I have some doubts about it as I've never done this kind of a thing before though.

1) how will my taxation, insurances and other paperwork go? I'd be living in Greece, but all my billing would still go through a Finnish company that is physically located in Finland. It seems taxation-wise it wouldn't make much a difference in my net earnings whether or not I'd have to pay all expenses to either country, but I'd obviously prefer to continue paying my side-expenses to Finland as I'm familiar with that bureaucracy.

2) Apartment search. It seems there are a lot of cheap apartments available on the internet, but some of them look just way too good to be true. Are apartments like this legitimate?

I'm inclined to believe, regardless of the economic situation, that a good apartment will still cost me a few hundred euros a month so anything below hundred just seems insanity, but there seems to be a lot of those available too in fairly good areas. Anything else I should keep an eye out on when scouting for a place to live in? Caveats or needed features and such?

Well, I guess those are my biggest concerns right now. I'd be only taking my computer and cat with me, so moving itself isn't an issue.

Thanks in advance!