Oh my gosh oh my gosh ITALY!
OK! Sorry got a bit excited but you have hit maybe the jackpot of LUCK!
On Sundays in Rome there is a HUGE flea market, maybe 1 mile long at least! Called Porta Portese! You can get there by taking the tram, and its in Trastevere in Rome. You basically just follow the Tiber
I used to go SOOOOO much when I lived there! So this was before I collected vintage toys but they do have everything! I would recommend spending the day there. Get up early - like 7 or 8am and just walk the whole path
Bring a backpack, and a snack since maybe cafes are closed on sundays. Also bring lots of cash and get ready to haggle!
If you go please let us know how it went! I loved that place!