As I didn't really found information about this topic in English it would be great if somebody from this platform could help me!
Do you speak (or at least read) Polish? If not, then the whole project might be too hard (as you'd need too much things translated).
- Allegro.pl: I heard that it is more popular than eBay because transaction costs are cheaper. Is this correct? Do you have more information?
Well, I think it hasn't much to do with the transaction costs. (althoug I don't have a first-hand experiences and information) I believe eBay simply screwed up, they entered our market (with the localized Polish version) too late, Allegro was already well-established and trustworthy (as much as online auctions can), being on the market for several years, it had a big client base, so nobody was rushing to sell/buy at eBay.
Besides (according to my friend, a regular seller at Allegro) eBay started badly in Poland, they had some serious problems (technical or organizational - the whole comments system was flawed and people were abusing it to boost their positive image as sellers), so many people, who checked them out of curiosity, returned to Allegro that was running more smoothly.
I'm sure they'll do well in the future, because they are big enough elsewhere, but they lost much time, just like for example PayPal, not present in Poland for too long, and when they entered the Polish market, you could basically only use them to pay, not to receive money. I opened an account with them but was disappointed with the limited offer, so I used them a few times and forgot about my account :)
And another problem with eBay and similar foreign companies (not depending on them, but influencing the market) are the spedition costs of European posts to Poland, I don't know if it has changed, but for years it was twice cheaper to send from Germany to let's say Sicily or Greece than to Poznań that is only 300 km away from Berlin.