Where can I buy real cheap historical low grade archaeological artifacts?

I own a few roman coins, which I like...but i'd like to own a bit more historical garbage...an ugly little broken piece of roman or anglo saxon pottery, , a single little piece of roman mosaic...a broken rusted out ring or broach etc... that sort of thing....next to worthless, but enjoyable for what they used to be. I don't know that I trust ebay or other retail sites.....it needs to be real, any doubt would ruin it, and much of these things would be sooo easy to fake...is there somewhere I can get these things with a bit of authentication behind it...I was thinking of a museum gift shop maybe somewhere in europe...or maybe some kind of historical foundation or archive that wants to thin its collection out a bit, sell off unimportant material etc..