i have an old cast iron bed since i was 13..im 48 now..any help of how much r worth?the people i got it from had it since before the ww1 and told me they r around the early 1900's..is in not bad shape..still have the original heavy duty metal box spring..but ,obviously i had to buy new mattress..is a full size one..dont know who made it or exactly the year was made..any help please..thanxs