You should check around at surplus outlets in your area. RS232 Terminals were used in great quantity in the days before PCs as the user I/O terminals on most computers. Very often you can find one for sale for very little money. Some brand names to look for:
Lear Sigler ADM
Beehive
Soroc
TeleVideo
DEC VT52
DEC VT100
Esprit
...plus many others. At one time there were probably 50 companies that manufactured video terminals.

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If you want to look at new product check out the web site of Esprit Systems. Look for what they are calling "traditional text terminals" on their web site.

Good Luck
Mike Karas