As with any firearm, it is not possible to accurately appraise a gun without seeing it. Recommend that you see a local gun dealer for an appraisal. You can also do your own investigation by looking at other models being sold that are in the same condition as yours. Try the gunbroker.com or a periodical called "The Gun List" You can also reference the Blue Book of Gun Values which can be purchased on line at various retailers.
100-10000 USD depending on specifics.
Please include the model number and gauge or caliber to get a answer to your question.Also include a serial number with letters in it,if there is some.
250 USD or so
50-600 usd
Not a valid Browning serial number.
50- 550 usd
100-10000 USD depending on specifics
All my research indicates that the 9Z prefix to your serial number belongs to the Browning 20 gauge light weight shotgun that was made in the year 1959.If you had a 12 gauge auto-5 magnum shotgun,then the prefix would be 9V.The value of each of these will be between 350-550 dollars,depending on overall condition and a good bore.
A Browning over and under is worth about $1,000-1,500 on it own and the fact that it's a Belgium made Browing increases the price significanly. I would say somewhere in the range of $500 to $750 more. The belgium made Browning is the most collectible and popular.
50-1000 usd
50-600 usd
Requires professional evaluation.