@healthnwell--There are a lot of metal detectors out there. Depending on what you and your husband are looking for, a hand-held metal detector is probably best.
If you do a search for metal detectors and include the type of place you wish to use it, a lot of options pop up.
The other thing to consider is the price range you are looking at. You can buy a metal detector for one hundred dollars on up to over one thousand.
When I purchased one for my husband, I made sure it came with a warranty and some different sized coils.
Have fun and good hunting!